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Fibromyalgia Symptoms, Physical Function, and Comorbidity in Middle-Aged and Older Adults Casey R. Shillam

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Kim Dupree Jones

b Background: Multiple studies report on symptoms or physical function in people with fibromyalgia; however, limited studies have been focused on older adults with fibromyalgia. b Objectives: The aims of this study were to describe the occurrence, frequency, severity, and distress of symptoms and to examine differences in symptoms and physical function between a middle-aged and an older group. b Method: Questionnaires were mailed to a random sample of 533 adults with fibromyalgia over 50 years of age, using a large tertiary care database. These questionnaires included an investigator-developed 29-item symptom questionnaire that measured the frequency (1Y4), severity (1Y4), and distress (0Y4) of FM symptoms. The participants also completed the Late Life Function and Disability Instrument and the Charlson Comorbidity Index. b Results: Fifty-three percent of the sample reported at least 20 symptoms in the last 7 days. The most frequent and severe symptoms were pain, nonrefreshing sleep, fatigue, stiffness, difficulty staying asleep, difficulty falling asleep, and profuse sweating. The most distressing symptoms were fear of symptoms worsening, followed by difficulty staying asleep, fatigue, nonrefreshing sleep, and restless legs. Participants reported moderate functional limitations (M T SD = 52.7 T 9.0). Comorbidities were low (1.7 T 1.5; range = 0Y7). The middle-aged group experienced a greater number of total symptoms (21.4 T 5.9 vs. 19.3 T 5.2; p G .01). b Discussion: Middle-aged adults with fibromyalgia were more symptomatic than older adults. Further study is needed to understand the relationship between fibromyalgia symptoms and age and physical function. b Key Words: aged & comorbidity & fibromyalgia & physical function & signs and symptoms

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ibromyalgia (FM), a debilitating multisymptom disorder, is defined by widespread pain lasting more than 3 months and eliciting pain in specific tender points found on the body during physical examination (Wolfe et al., 1990). Fibromyalgia affects between 6 million and 10 million people nationally, with an annual direct cost of over $20 billion per year (Robinson et al., 2003). Prevalence estimates range from 4% to 7% of the general adult population, with higher prevalence in women, and increasing with age (Gowin, 2000; Wolfe, Ross, Anderson, Russell, &

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Lois Miller

Hebert, 1995). As people age, they have increased risk of pain-inducing, function-limiting comorbid conditions that add to their disease burden. Little is known about changes in symptoms and function as people with FM age and experience other chronic conditions. People with FM report many symptoms and decreased physical function (Liedberg, Burckhardt, & Henriksson, 2006; Rutledge, Jones, & Jones, 2007; Sprott & Muller, 1998). The National Fibromyalgia Association (NFA) recently conducted the first study of a large national sample through an online survey (Bennett, Jones, Turk, Russell, & Matallana, 2007). In their sample of 2,595 people with a mean age of 47.3 T 10.7 years, the most frequent symptoms were low back pain (63%), recurrent headaches (47%), muscle spasms (46%), fatigue (40%), and depression (40%); 62% of the sample experienced poor physical function. In addition to the difficulty of managing multiple chronic comorbid conditions associated with aging, the symptoms resulting from those comorbidities are multidimensional. Dimensions common to all symptoms include occurrence, frequency, severity or intensity, duration, distress, quality, location, and affective impact. Symptoms are defined as a subjective experience of change in normal biopsychosocial functioning and include an emotional response to the occurrence of the symptom (Dodd et al., 2001; Lenz, Pugh, Milligan, Gift, & Suppe, 1997). Most studies of symptoms in those with persistent pain syndromes, such as FM, use either the frequency or the severity of the symptoms to determine the impact that those symptoms have on the participants’ lives (Bennett, 2002; Bookwala, Harralson, & Parmelee, 2003; Sprott & Muller, 1998). However, research in symptoms associated with cancer treatment has demonstrated that the severity and distress of symptoms are most predictive for outcome variables such as poor physical function and quality of life (Chang, Hwang, Feuerman, Kasimis, & Thaler, 2000; Given, Given, Azzouz, & Stommel, 2001). Symptom distress has been Casey R. Shillam, PhD, RN-BC, is Postdoctoral Fellow, Betty Irene Moore School of Nursing, University of California, Davis, Sacramento. Kim Dupree Jones, PhD, RNC, FNP, is Associate Professor, School of Nursing, Oregon Health and Science University, Portland. Lois Miller, PhD, RN, FGSA, FAAN, is Visiting Professor, Betty Irene Moore School of Nursing, University of California, Davis, Sacramento. DOI: 10.1097/NNR.0b013e31822bbdfa

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310 Fibromyalgia Symptoms and Physical Function shown to have a significant impact on the expression of symptoms in people with FM (White, Nielson, Harth, Ostbye, & Speechley, 2002). A recent study evaluating the distress dimension found that up to 83% of those with FM reported distress, exacerbating their FM symptoms (Bennett et al., 2007). Although FM studies have not included each of the dimensions of frequency, severity, and distress of FM symptoms specifically, the predictive value of collective appraisal of these dimensions clearly supports a comprehensive evaluation of symptom expression. FM and Aging Many people with FM are aging, and not much is known about FM in older adults. Although FM is a complicated syndrome in the general population, these complexities are compounded in the older adult due to issues associated with the aging process. These issues include an increasing number of comorbid conditions, increasing symptoms associated with multiple chronic diseases, and declining physical function. Despite emerging knowledge about chronic diseases and aging, little is known about the impact of age on FM. Comorbidity Older adults are more likely to have comorbid conditions with advancing age (Yancik et al., 2007). Comorbidity is defined as the concurrent presence of two or more chronic medical diagnoses in an individual (Valderas, Starfield, Sibbald, Salisbury, & Roland, 2009). Comorbidity affects more than 35% of those 65 years of age and increases to over 70% by 80 years of age (Valderas et al., 2009). Increased complexity of comorbid conditions includes one condition worsening other conditions or increasing risk for another condition. In addition, multiple concurrent conditions often have a synergistic effect on an outcome such as symptom management or physical function (Yancik et al., 2007). Common comorbidities found in FM populations include osteoarthritis, thyroid disease, diabetes mellitus, obesity, and rheumatic arthritis (Bazzichi et al., 2007; Bernatsky, Dobkin, De Civita, & Penrod, 2005; Shaver, Wilbur, Robinson, Wang, & Buntin, 2006; Wolfe et al., 1995). Evidence suggests that the trend of increasing prevalence of comorbidity and functional decline with advanced age may not be due to higher rates of incidence in the aged population but rather may be linked to greater awareness of different health conditions and improvements in the screening and diagnostic testing for those conditions (Crimmins & BeltranSanchez, 2011). Decreases in functional limitations (Martin, Freedman, Schoeni, & Andreski, 2010) and disability prevalence (Manton, Gu, & Lamb, 2006) in older adults in the United States and other Western societies may be attributed to early identification of diseases leading to successful management before disability onset. These data are contradictory to the traditional perspective of greater functional declines with advanced age. This emerging evidence highlights the critical need for understanding the disabling effects of FM in the older adult population. Functional Outcomes of FM Poor physical function in older adults with FM poses further limiting effects than in the general population of aged adults.

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Poor physical function is correlated with greater risk for disability and increased financial burden that ultimately places older adults at risk for loss of independence (Boyd et al., 2007; Guralnik, Fried, & Salive, 1996). In populations of older adults, persistent pain is associated strongly with lower physical function (Bookwala et al., 2003), loss of mobility (Jakobsson, Klevsgard, Westergren, & Hallberg, 2003), and higher levels of disability (Al Snih, Raji, Peek, & Ottenbacher, 2005). Therefore, the aging FM population may be at an even greater risk for functional decline and institutionalization. Research in Older Adults With FM Complications of aging in the FM population have received limited attention in the literature. The few studies that did evaluate aging populations with FM had serious limitations. Multiple studies defined older adults as over 50 years of age and had samples with mean ages under 65 years of age (Burckhardt, Clark, & Bennett, 2001; Valkeinen, Hakkinen, Hannonen, Hakkinen, & Alen, 2006). Another limitation is the conflicting findings among different studies. For example, in one study, it was demonstrated that a middle-aged sample experienced greater severity of pain, depression, and sleep disturbance compared with an older sample, whereas another study demonstrated that an older sample had greater symptom severity compared with a middle-aged group (Cronan, Serber, Walen, & Jaffe, 2002; Pamuk & Cakir, 2005). Specific Aims The purpose of this study was to address the critical gaps of insufficient data on older adults with FM and the conflicting findings in the state of the science on aging with FM. The study was designed to describe a more comprehensive set of symptoms in an older adult sample with FM. In addition, the study was focused on identifying FM symptom dimensions of frequency, severity, and distress as these dimensions best predict physical function in other populations (Chang et al., 2000; Given et al., 2001). Finally, the sample included a truly older adult population as defined by the American Geriatric Society as over 65 years of age, and data analysis compared those 50 to 64 years of age with those 65 years or older on multiple outcomes. The aims of this study were to describe the occurrence, frequency, severity, and distress of FM symptoms and to examine differences in symptoms and physical function between the middle-aged and older groups. It was hypothesized that those 65 years or older would report more symptoms and comorbidities and have poorer physical function than would the middle-aged sample.

Methods A random sample of 533 patients was drawn from an FM patient database of over 5,000 community-living FM patients at a large academic medical center in the Pacific Northwest. The database consists of persons diagnosed with FM (ICD-9 729.1) who had been examined in clinical practice or had participated in previous FM clinical trials. The database was limited to those between 50 and 64 years of age, and through random selection, 250 were invited

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to participate. Further database limitations were made to those over 65 years of age, and 283 were invited to the study. The study protocol was approved by the institutional review boards of the academic medical center and sponsoring institution, and informed consent was obtained from all participants. Inclusion criteria were (a) ages 50 years or older, (b) diagnosis of FM based on the 1990 American College of Rheumatology classification criteria (Wolfe et al., 1990), (c) experience of at least one symptom in addition to pain over the last 7 days, and (d) ability to read English. Power was computed with nQuery Advisor 5.0, indicating a sample size of 110 for detecting a medium effect size. Measures Data were collected through four self-report measures and a demographic questionnaire that were mailed to participants. Demographic data included year of diagnosis with FM, years with FM symptoms (a period usually longer than year diagnosed), age, race and ethnicity, and gender. The questionnaire took approximately 45 minutes to complete. Because participants were able to answer the questions in their own homes, the instructions encouraged them to complete each measure separately and to take breaks to avoid fatigue. No reminders were provided to encourage the return of the questionnaires. FM Symptoms Symptoms were assessed using a checklist of

29 symptoms, 24 of which were identified in the previously described Internet-based FM survey (Bennett et al., 2007). Content validity was established with preliminary administration of the 24-item checklist to a convenience sample of 10 participants from a local FM support group. This sample identified an additional five signs and symptoms: (a) sweating or feeling hot, (b) bruising easily, (c) sensitivity to light, sound, or smell, (d) cold hands or feet, and (e) skin tenderness. The checklist is adapted from the Memorial Symptom Assessment Scale (MSAS; Portenoy et al., 1994) and is composed of occurrence (yes or no), frequency, severity, and distress dimensions for each symptom. Symptom dimensions were measured on a 1 (least) to 4 (most) Likert scale for frequency and severity and a 0 (not distressing) to 4 (most distressing) Likert scale for distress (the zero option for distress was offered because the occurrence of a symptom may not cause any distress). Scores on frequency, severity, and distress for each symptom were summed to create a composite symptom impact score ranging between 0 and 12, with higher numbers indicating more overall symptom impact. Pain Severity Pain was measured using the Brief Pain In-

ventory (M.D. Anderson Cancer Center, 2004). This instrument was developed originally for cancer patients and has been validated for use with FM, arthritis pain, diabetic neuropathy, postherpetic neuralgia, and persistent nonmalignant pain and has been validated for use specifically with older adults (Zelman, Gore, Dukes, Tai, & Brandenburg, 2005). The Brief Pain Inventory has two subscales: severity of pain on a scale of 0Y10 for pain at its worst, at its least, on average, and right now, and the interference pain causes (0Y10) with various activities such as walking, sleeping, and

work. Overall score is calculated with arithmetic average of severity and interference items. Perceived Physical Function Perceived physical function was

measured with the Late Life Function and Disability Instrument (LLFDI; Haley et al., 2002). The LLFDI is a self-report measure that has been correlated with physical performance tests and is acceptable as an effective substitute when physical testing is not possible (Sayers et al., 2004). Internal consistency values range between .63 and .86; testYretest reliability is reported above .90; and adequate concurrent, predictive, and content validities have all been demonstrated (Haley et al., 2002; McAuley, Konopack, Motl, Rosengren, & Morris, 2005; Sayers et al., 2004). The LLFDI has two subscales, the Disability Component and the Function Component, each of which has been validated as a stand-alone scale. For this study, analysis focused on the Function Component (Haley et al., 2002). The Function Component consists of 32 items with a range of 1Y5. Lower scores indicate more limitations in physical function. Raw scores were transformed according to the scoring instructions to a 0Y100 score then grouped into instrumentdefined categories ranging from no functional limitation (score greater than 76) to severe functional limitation (score less than 42; Haley et al., 2002). Comorbidity Comorbidity scores were summed on the Charlson Comorbidity Index (CCI), a weighted index with scores ranging from 0 to 41, with higher scores reflecting more chronic conditions (Charlson, Pompei, Ales, & MacKenzie, 1987). A validated self-report version of the CCI, with testY retest reliability ranges between .91 and .92, was used in this study (Katz, Chang, Sangha, Fossel, & Bates, 1996).

Statistical Methods Descriptive statistics and plots were used to describe the frequency, severity, and distress of each symptom and for demographic information. Scores on frequency, severity, and distress for each symptom were combined to create a composite symptom impact score. Although the checklist was patterned on the MSAS (Portenoy et al., 1994), this was the first use of the checklist, and it is not yet known which symptom dimensions can be combined to form subscale scores. Therefore, rather than calculating averages from certain specified symptom dimensions as is conducted with the MSAS for analysis and interpretation of the data, a total composite score was calculated as a total of all three dimension scores. Multivariate analysis consisted of t tests to examine differences in the middle-aged and older groups in symptoms, comorbidities, and physical function.

Results Of 533 participants, 171 returned the questionnaires, for a 39% response rate. All returned questionnaires met the inclusion criteria for the study, as the surveys were mailed only to those who qualified for study participation. Missing data were minimal; therefore, any missing data were excluded from analysis. Twice as many respondents were 50 to 64 years of age (n = 114, 57.3 T 4.3 years of age) as

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TABLE 1. Demographic and Clinical Characteristics of People With FM Demographic and clinical variables

Total sample (n = 171)

Female, n (%) Age, M T SD (range), years Race, n (%) Multiple races indicated Asian American Indian/Alaska Native White Hispanic/Latino Body mass index, n (%) Underweight (G18.5) Normal (18.5Y24.9) Overweight (25Y29.9) Obese (Q30) Years with FM symptoms, M T SD (range) Years diagnosed with FM, M T SD (range) Physical function scores (0Y100), M T SD (range) Comorbidity score, M T SD (range) Number of symptoms (0Y29), M T SD (range) Overall symptom impact (0Y12), M T SD (range)

165 (96.5) 60.7 T 6.2 (50Y76) 9 2 12 163 1 2 49 58 59 21.8 T 13.2 13.3 T 7.1 52.7 T 9.0 1.7 T 1.5 19.9 T 5.4 4.9 T 1.9

(5.3) (1.2) (7) (95.3) (0.6)

Middle-aged group (n = 114) 110 (96.5) 57.3 T 4.3 (50Y64) 7 2 10 107 1

(1.2) (28.7) (33.9) (34.5) (4Y69) (0Y39) (31.5Y77.5) (0Y7) (6Y29) (0.4Y10.5)

2 36 36 38 19.1 T 11.6 12.3 T 7.0 52.8 T 9.1 1.7 T 1.5 20.6 T 5.5 5.2 T 2.0

(6.1) (0.9) (8.8) (93.9) (0.9) (1.8) (31.6) (31.6) (33.3) (4Y59) (0Y37) (31.5Y76.0) (0Y7) (6Y29) (1.3Y10.5)

Older group (n = 57) 55 (96.5) 67.7 T 2.7 (65Y76) 2 1 2 56 0

(3.5) (1.8) (3.5) (98.2) (0)

0 (0) 13 (22.8) 22 (39.6) 21 (36.8) 27.3 T 14.5 (8Y69)* 15.4 T 7.0 (2Y39) 52.5 T 8.9 (32.6Y77.5) 1.8 T 1.4 (0Y6) 18.6 T 5.1 (6Y29)* 4.4 T 1.8 (0.4Y8.3)*

Note. FM = fibromyalgia. *Significant difference between the middle-aged and the older group, p G .05.

those over 65 years of age (n = 57, 67.7 T 2.7 years of age). The overall sample was predominantly female and Caucasian (Table 1). The mean duration of FM symptoms for the entire sample was 8.5 T 12.4 years, and 68.4% of the sample was either overweight or obese. The sample reported an average of 20 of the possible 29 symptoms. The mean physical function scores indicated a moderate functional limitation. Comprehensive Set of Symptoms in the Sample An average of 20 symptoms (range = 6Y29) were reported. Most commonly reported were pain (100% of the sample), stiffness (99%), fatigue (95%), nonrefreshing sleep (93%), forgetfulness (87%), difficulty staying asleep (85%), and muscle spasms (81%; Table 2). The least reported symptoms were feeling like a burden to others (66%) and pelvic pain (59%). Although pain did not have the highest overall symptom impact, it was second behind fatigue, and all three sleep-related symptoms were high in the rank order for overall symptom impact (Table 2). The highest composite scores were for fatigue (8.69 T 3.11), pain (8.45 T 2.26), nonrefreshing sleep (8.41 T 3.36), stiffness (7.99 T 2.66), difficulty staying asleep (6.95 T 3.84), and difficulty falling asleep (6.03 T 4.29; Table 2). There were marked differences in the rank order for each symptom in the dimensions of frequency, severity, and distress on the FM symptom checklist (Cronbach’s ! = .94). The most frequent symptoms were pain (3.4 T 0.8), nonrefreshing sleep (3.38 T 1.22), and fatigue (3.37 T 1.11; Table 3). The most severe symptoms were nonrefreshing sleep (2.77 T 1.13),

fatigue (2.77 T 1.05), and difficulty falling asleep (2.58 T 1.40). The most distressing symptoms were fear of symptoms worsening (3.24 T 1.34), difficulty staying asleep (3.08 T 1.26), and fatigue (2.99 T 1.18). Differences Between the Age Groups The CCI scores in this sample ranged from 0 to 7 (Cronbach’s ! = .78), with 77% of the sample having a score of at least 1, indicating at least one comorbid condition (Table 4). The most common comorbid conditions included osteoarthritis (n = 85, 49.7%), thyroid disease (n = 64, 37.4%; n = 52 hypothyroid), difficulty hearing (n = 52, 30.4%), asthma (n = 41, 24%), diabetes mellitus (n = 18, 10.5%), chronic obstructive lung disease (n = 15, 8.8%), stroke (n = 11, 6.4%), and rheumatic arthritis (n = 11, 6.4%). There was no significant difference in the comorbidity scores, t(169) = j0.59, p = .55, between the two age groups. The duration of FM symptoms was significantly different between the middle-aged and older groups (19 and 27 years’ duration, respectively), t(156) = j3.84, p G .01. Both groups reported pain, fatigue, and nonrefreshing sleep as the most frequently experienced symptoms and fatigue and nonrefreshing sleep as the most severe symptoms. However, differences in the distress caused by symptoms were noted, with fear of symptoms worsening, difficulty staying asleep, and restless legs as the most distressing to the middle-aged group and fatigue, nonrefreshing sleep, and irritable bowel as the most distressing to the older

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TABLE 2. Symptom Prevalence and Overall Symptom Impact (N = 171)

Symptom Pain Stiffness Fatigue Nonrefreshing sleep Forgetfulness Difficulty staying asleep Muscle spasms Skin tenderness Difficulty concentrating Difficulty falling asleep Sensitivity to light or sound Profuse sweating or feeling hot Anxious Sad Cold hands Bruising easily Irritable bowel Swelling Inability to enjoy life Irritable bladder Falling easily Restless legs Accident prone Headaches Easily angered Fear of symptoms worsening Feeling dizzy Feel like a burden to others Pelvic pain

Composite % of symptom impact sample score (0Y12), M T SD n reporting 171 170 163 159 149 146 138 134 130 128 128 125 123 114 113 113 106 104 101 99 99 98 97 96 94 93 90 66 59

100 99 95 93 87 85 81 78 76 75 75 73 72 67 66 66 62 61 59 58 58 57 57 56 55 54 53 39 35

8.45 7.99 8.69 8.41 5.89 6.95 5.64 5.43 5.70 6.03 5.77 5.65 4.34 4.45 4.66 4.26 4.75 3.83 4.23 4.20 3.72 3.60 3.24 3.81 3.27 3.98 2.75 2.78 2.24

T T T T T T T T T T T T T T T T T T T T T T T T T T T T T

2.3 2.7 3.1 3.4 3.3 3.8 3.6 3.7 3.8 4.3 4.1 4.0 3.4 3.9 4.0 3.6 4.2 3.7 4.1 4.2 3.7 3.7 3.3 3.9 3.5 4.2 3.1 4.0 3.4

group. The middle-aged group experienced a significantly greater number of total symptoms (21.4 T 5.9 vs. 19.3 T 5.2), t(169) = 2.33, p = .02, and significantly greater overall symptom impact than the older group did in five symptoms: difficulty falling asleep, difficulty staying asleep, being accident prone, easy bruising, and unexplained sweating. Both groups experienced similar rates of moderate functional limitation (middle-aged, 52.9 T 9.2 vs. older, 53.2 T 8.7), t(169) = 0.23, p = .82.

Discussion This study yielded three novel findings: (a) The total sample reported a very high number of symptoms (19.9 T 5.4), supporting the most recent FM symptom studies; (b) the

distress dimension in the total sample yielded a markedly different rank order than the frequency and severity dimensions did; and (c) differences between the age groups were unexpected: The middle-aged group reported significantly more symptoms than the older group did, and no differences were found between the two age groups on comorbidity or physical function. The hypothesis that those 65 years or older would report more symptoms and comorbidities and have poorer physical function than the middle-aged sample would was not supported by the findings of this study. Symptoms Over half of the sample reported that they had experienced at least 20 symptoms in the past 7 days. This average is higher than that reported in early FM studies of 8 to 15 symptoms (Bennett, 2002; Sprott & Muller, 1998) yet reflects the findings of the NFA study report of 20.3 T 3.1 symptoms (Bennett et al., 2007). The discrepancy between the most current findings and previous early research may be due to more broadly offered symptom choices in the instrumentation. For example, this study measured 29 symptoms; the NFA study measured 24 symptoms. In addition, this study drew its sample from a tertiary healthcare setting that is a specialty FM clinic, and therefore, the patients in this clinic may experience greater numbers of more severe symptoms. Symptom Dimensions Although the rank orders of symptom frequency and severity were similar, the distress dimension varied. As expected, pain, fatigue, sleep-related symptoms, and stiffness were the most frequent and severe symptoms in the total sample, mirroring previous studies (Bennett et al., 2007; Liedberg et al., 2006). However, the most distressing symptom was fear of symptoms worsening; feeling like a burden to others and inability to enjoy life were ranked 7 and 8, respectively, much higher than the frequency and severity dimensions. Although fatigue, nonrefreshing sleep, and pain were also in the top 6 symptoms in order of distress, the emotional symptoms of fear, burden, and inability to enjoy life are of important consequence. The literature supports the finding that emotional symptoms add to the distress of physical symptoms (Liedberg et al., 2006; Rutledge et al., 2007). Therefore, nurses should assess for the presence of emotional symptoms in conjunction with the physical symptoms and target interventions to both. Differences Between the Middle-Aged and Older groups Comparison of Symptom Expression Symptom expression

differed significantly between the middle-aged group and the older group. The middle-aged group had significantly more symptoms (21) compared with the older group (19). The effect size for the difference (Cohen’s d = .38) indicates a moderate effect in the total number of symptoms between the two groups, validating the power analysis. In addition, the middle-aged group displayed significantly greater overall symptom impact than did the older group for difficulty falling asleep, difficulty staying asleep, being accident prone, easy bruising, and unexplained sweating. Other studies report similar findings in which younger and middle-aged samples expressed more severe symptoms than older samples did (Cronan et al., 2002; Liedberg et al., 2006).

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TABLE 3. Symptoms Compared by Rank Order for Frequency, Severity, and Distress Dimensions for the Top 15 Symptoms Rank Order 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Symptom frequency

Symptom severity

Symptom distress

Pain Nonrefreshing sleep Fatigue Stiffness Difficulty staying asleep Difficulty falling asleep Sensitivity to light or sound Cold hands Skin tenderness Bruising easily Profuse sweating or feeling hot Difficulty concentrating Irritable bowel Irritable bladder Fear of symptoms worsening

Nonrefreshing sleep Fatigue Difficulty falling asleep Difficulty staying asleep Profuse sweating Stiffness Pain Sensitivity to light or sound Irritable bowel Cold hands Irritable bladder Fear of symptoms worsening Headaches Feel like a burden to others Difficulty concentrating

Fear of symptoms worsening Difficulty staying asleep Fatigue Nonrefreshing sleep Restless legs Pain Feel like a burden to others Inability to enjoy life Irritable bowel Difficulty falling asleep Profuse sweating Difficulty concentrating Stiffness Irritable bladder Sensitivity to light or sound

Note. Capturing ‘‘pain’’ in bold as the most frequent symptom demonstrates where it lies in the rank order for severity and distress. Capturing ‘‘nonrefreshing sleep’’ in italics as the most severe symptom demonstrates where it lies in the rank order for frequency and distress. Capturing ‘‘fear of symptoms worsening’’ in bold-italics as the most distressing symptom demonstrates where it lies in the rank order for frequency and severity.

Younger persons who are newer to the diagnosis of FM are known to improve in a number of symptom and functional status measures in the first 1 to 3 years of diagnosis (Liedberg et al., 2006; White et al., 2002). Some patients resolve these issues with lifestyle changes (e.g., fewer hours of employment and pacing), creation of a new concept of identity, and improved medical management. In addition, research has established that older adults are often better q

TABLE 4. Comorbidity Information From the CCI CCI score, M T SD Total sample 50- to 64-year-old group 65 years or older group Range of CCI scores, n (%) 0 1 2 3 4 5 6 7 Note. CCI = Charlson Comorbidity Index.

1.7 T 1.47 1.6 T 1.50 1.8 T 1.42 40 48 37 29 9 5 1 2

(23) (28) (22) (17) (5) (3) (1) (1)

able to modify their daily routines and cope better with both the symptoms and the expectations they have for their symptom experiences (Crimmins & Beltran-Sanchez, 2011; Martin et al., 2010). With the older sample demonstrating an additional decade of experiencing symptoms compared with the middle-aged group, the significant difference in symptom expression between the middle-aged and older groups may be a result of more experience with managing symptoms, better coping skills, or changes in lifestyle or expectations. Comparison of Comorbidity An unexpected finding revealed

no significant differences in comorbidity between the two age groups. Previous research in general older adult populations reveals higher numbers of comorbid conditions with increasing age in those over 60 years old (Boyd et al., 2007; Guralnik et al., 1996). Research specific to FM demonstrates similar findings to the general population, as Cronan et al. (2002) demonstrated: an older sample had significantly more comorbid conditions than both younger and middle-aged samples did. The unexpected finding of similar comorbidity between the two age groups in this study may be explained by the limited age range of the older group (65 to 76 years). One comorbidity commonly associated with complications in FM is obesity, defined as body mass index (BMI) greater than 30 by the Centers for Disease Control and Prevention. The current findings were consistent with the Centers for Disease Control and Prevention data regarding BMI in FM. Although there were no significant differences in BMI between the two age groups, nearly 70% of the total

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sample had a BMI of 25 or higher, indicating that the majority of the sample was either overweight or obese. Higher levels of BMI are found in the majority of those with FM in the United States, with positive correlation between high BMI, increasing age, higher numbers of symptoms, and lower physical function (Shaver et al., 2006). Another unexpected finding was CCI scores much lower than supporting research would indicate (Boyd et al., 2007; Guralnik et al., 1996). The literature is replete with references to comorbidity in FM: osteoarthritis (Wolfe et al., 1995), thyroid disease (Bazzichi et al., 2007), diabetes mellitus (Bernatsky et al., 2005), and rheumatic arthritis (Shaver et al., 2006), and such a low number of comorbid conditions is unusual. Although one explanation may be that this FM sample does not represent the entire population of FM patients, a more likely cause may be the assumption of ineligibility. Thirty-two questionnaires were returned unanswered, with the participant writing on the front that he or she would not be eligible to participate due to the presence of numerous chronic conditions. This was not an exclusion criterion. The early years of FM research required excluding those with multiple comorbid conditions to be able to more accurately describe the specific manifestations of the syndrome. It is possible that this population has been socialized to believe that they cannot participate in research with comorbidities. The paucity of evidence about the management of FM in people with comorbid medical conditions is cause for great concern, particularly in an aging population. Comparison of Physical Function No difference existed between the two age groups on perceived physical function. Although low levels of physical function are a common manifestation in FM (Rutledge et al., 2007; Shaver et al., 2006), physical function is typically lower in younger and middleaged groups compared with older groups (Burckhardt et al., 2001; Valkeinen et al., 2006). However, these studies also encounter the limitation of the older age sample only going up to 65 years of age. This study was targeted on an older group specifically over 65 years of age, and the results show moderate function limitations in both the middle-aged and older groups, 52.8 versus 52.5, respectively. There are at least two possible explanations for this unexpected finding: (a) Previous studies used older adult populations that were younger than 65 years of age or (b) measures of physical function in previous work have not been specific or sensitive enough to accurately measure levels of physical function specifically in older adult populations. Most studies comparing the level of physical function between different age-group samples of those with FM use the Fibromyalgia Impact Questionnaire physical function subscale. This subscale, although specific for FM, has poor validity when compared with objective measures of physical function (Bennett, 2005). The LLFDI, on the other hand, was developed specifically for older adult populations and has been correlated with physical performance tests (Haley et al., 2002). It is possible that function was similar in older versus middle-aged adults because the LLFDI is a more sensitive instrument for evaluation of functional impairment.

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Limitations Several methodological limitations may affect the interpretation of the data. First, the descriptive, correlational, crosssection study design limits causal analysis or inferences and therefore reports relationships only. Second, the sample was drawn from a tertiary healthcare setting specifically for FM consultation and treatment and may not be representative of the greater population of those with FM (e.g., patients may have more severe or recalcitrant FM). Therefore, this sample’s symptom experience may have been more severe than that of those patients not referred to specialty care. Finally, only one-third of the sample was over the age of 65 years, which limits the power of statistical analysis comparing the two groups. It is also unclear how differences in gender or ethnicity may contribute in variation of symptoms in FM. This study had very limited variability in both gender and ethnicity; this limitation warrants further study in the future. Last, the inclusion of patients with arthritis or other comorbid conditions prevents the conclusion that all symptoms reported solely represent symptoms of FM. Any of these limitations to the study could contribute to the lack of support of the research hypothesis. Future Research Directions and Implications for Nursing Practice Future research is needed to confirm self-report physical function measures with standardized objective laboratory tests of physical function. In future research, patterns of decline in physical function should be studied over a more heterogeneous sample. Although physical function is more limited in younger and middle-aged samples of those with FM than in older healthy adults, older adults with other persistent pain diagnoses have greater functional declines as they age. In future research, those specific age groups classified by the American Geriatric Society guidelines that categorize older adult populations of 65 to 74 years of age as young-old, 75 to 84 years as middle-old, and 85 years and over as oldold must be distinguished. As well, the causal relationship between FM and lower levels of physical function in older samples must be evaluated. It is unclear if the limitations in physical function in advancing age occur as a result of the disease process of FM or from conditioning and health status related to comorbidities. Nurses in clinical practice should consider evaluation of the three dimensions of symptoms: frequency, severity, and distress, as differences in each dimension may lead practitioners to alternative treatments. For example, a patient whose most distressing symptom is ‘‘fear of worsening’’ could be offered data about the common, stable, nonprogressive course of the illness. Cognitive behavioral therapies, such as decreasing catastrophic thinking, could be employed. Reports of fatigue frequency, for example, could encourage clinicians to prescribe time-based pacing activities and fatigue management rest and exercise protocols. Reports of pain or sleep disturbance severity could yield targeted pharmacologic intervention. Nurses are charged with ensuring that, through symptom management, patients are able to maintain their highest possible level of physical function and quality of life. Although much has been discovered in the pathophysiology and treatment of FM and the expression of symptoms in this

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316 Fibromyalgia Symptoms and Physical Function syndrome, there remain significant gaps in the understanding of the effect of aging and comorbidity on physical function in an aging population. These gaps require further investigation as our population continues to age to better understand comorbidities associated with aging in those with FM and the influence of aging on symptoms in FM. q Accepted for publication June 20, 2011. Funding for this research was provided by The John A. Harford Foundation Program: Building Academic Geriatric Nursing Capacity; Sigma Theta Tau International, Beta Psi Chapter; and the Oregon Health and Science University Dean’s Award. The authors have no conflicts of interest to disclose. Corresponding author: Casey R. Shillam, PhD, RN-BC, Betty Irene Moore School of Nursing, University of California, Davis, 4610 X Street, Suite 4202, Sacramento, CA 95817 (e-mail: casey.shillam@ucdmc. ucdavis.edu).

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