Rheumatology Advance Access published August 25, 2012

RHEUMATOLOGY

Original article

doi:10.1093/rheumatology/kes215

Disease impact of hand OA compared with hip, knee and generalized disease in specialist rheumatology health care Rikke Helene Moe1,2, Margreth Grotle1,3, Ingvild Kjeken1, Ka˚re Birger Hagen1,2, Tore K. Kvien4 and Till Uhlig1,4 Abstract Objective. To describe and compare disease impact in patients with hand OA with those with hip, knee and generalized disease. Methods. Patients with OA referred to a specialized rheumatology clinic (408 patients, 86% women) were included in a cross-sectional study. They were examined by a rheumatologist and classified into primary hand, hip, knee and/or generalized (more than two joint localizations) OA. Patient-reported disease impact was collected on numeric rating scales (pain, fatigue), Hopkins Symptom Checklist-25 (emotional distress), Western Ontario and McMaster and Australian/Canadian Hand OA indexes (disease-specific functioning), Short Form 36 (generic health-related quality of life) and a co-morbidity checklist.

Conclusion. OA patients referred to specialist care reported considerable levels of disease impact across localizations. Regardless of functional impairments related to the primary OA localization, patients generally reported high levels of impaired disease-specific functioning at other sites. In the management of OA clinicians should also consider functioning in joint sites other than the primary OA localization. Trial registration. Current controlled trials, www.controlled-trials.com, ISRCTN25778426. Key words: OA, hand, disease impact, co-morbidity, health status, symptom, function, localization.

Introduction OA is one of the most frequent chronic musculoskeletal disorders, and one of the leading causes of pain and 1 Department of Rheumatology, National Resource Center for Rehabilitation in Rheumatology, Diakonhjemmet Hospital, Oslo, Norway, 2Faculty of Medicine, Institute of Health and Society, The University of Oslo, Norway, 3FORMI, Clinic for surgery and neurology (C1), Oslo University Hospital, Oslo, Norway, 4Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.

Submitted 9 March 2012; revised version accepted 3 July 2012. Correspondence to: Rikke Helene Moe, Department of Rheumatology, National Resource Center for Rehabilitation in Rheumatology (NRRK), Diakonhjemmet Hospital, PO Box 23, Vinderen, No-0319 Oslo. E-mail: [email protected]

disability [1]. The hands, hips and knees are frequent sites of disease involvement in OA [2–4]. Symptomatic hand OA significantly increases with age and the prevalence is higher in women than in men [2, 5]. In Norway the prevalence of self-reported hand OA is 4.3% [6], and in the Netherlands the prevalence of symptomatic hand OA is 11% [7]. Patients with hand OA have reduced grip strength and more activity limitations than people without hand OA [5], which may have an impact on the patients health-related quality of life [8, 9]. Further, patients with OA are known for having co-morbidities and higher BMI, adding to the disease impact [10]. In research, patient populations with OA are mostly examined for a specific localization of the disease in

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CLINICAL SCIENCE

Results. Considerable disease impact was detected across all localizations: patients scored >5 on pain (range 0–10), had on average two co-morbidities and scored >1.5 on emotional distress (Hopkins Symptom Checklist-25, range 1–4). Patients with hand OA scored poor on disease-specific functioning of the lower extremities, and patients with lower extremity OA also scored poor on disease-specific hand functioning. Patients with hand OA scored better on pain (P = 0.001, one-way analyses of variance) and the Short Form 36 Health Survey physical component (P < 0.001), whereas no major differences were observed for the mental component (P = 0.07).

Rikke Helene Moe et al.

FIG. 1 Flow chart of patients included in the present study. Eligible (n = 531)

Consent (n = 411)

No consent (n = 130; men, n = 25; women, n = 105)

Not included Other diagnosis (n = 1) Severe multi-trauma (n = 1)

Included (n = 408, 77%)

Hand OA (n = 270, 66%)

Hip OA (n = 33, 8%)

hand, hip or knee, whereas little knowledge exists about symptoms and functioning in joints other than in the primary OA localization. More knowledge concerning the relationship between localization of OA and disease impact could contribute to a more targeted treatment and prevention approach in OA [11], especially when focusing on non-pharmacological approaches. The overall objective of this study was to describe and compare disease impact measured by symptoms, functioning and health-related quality of life across groups of patients with OA in hands, hips, knees and generalized OA. The following three hypotheses were stated: (i) High levels of pain, a high BMI and frequent co-morbidities are seen in all OA localizations. (ii) Patients with hand OA have poor hand functioning but good functioning in the lower extremities. (iii) Overall physical and mental functioning in hand OA will be scored similarly to hip and knee OA.

Methods Participants and demographics From patients referred to a study on a multidisciplinary OA programme [12], a total of 408 participants aged between 40 and 80 years were recruited for this cross-sectional study. Four hundred and eight (77%) participants of the 531 eligible contributed data in this study (Fig. 1). The clinical diagnosis of hand, hip or knee OA was made by

2

Withdrew before baseline (n = 1)

Knee OA (n = 75, 19%)

Generalized OA (n = 30, 7%)

a rheumatologist according to the primary localization of complaints, and classification into these categories was performed by a rheumatologist, in most cases with access to radiographs to support a clinical diagnosis. Some of the patients clearly had a more generalized disease, with two or more affected joint groups [13], and were classified as generalized OA. OA manifestation of the spine was not a part of the investigation. If the OA diagnosis could not be clinically confirmed during the examination by the rheumatologist, the participant was excluded. Other exclusion criteria were recent surgery or severe trauma in the extremities, RA, primary crystal arthritis, current cancer, severe cognitive impairments or inability to read and understand the Norwegian language. All patients involved in the project signed informed consent and were informed according to the Declaration of Helsinki. The data inspectorate and the regional ethics committee reviewed and approved the project (regional ethics committee ref. 156-06073 1.2006.598); ISRCTN trial number 25778426.

Outcome measures Before clinical examination, all patients completed the same standardized set of patient-reported outcomes, including instruments for measuring symptoms, functioning and health-related quality of life. The questionnaire

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Disease impact of hand OA

also included information on socio-demographics (age, gender, height, weight, marital status, work situation, emotional distress and physical activity), and patients ticked a list of 11 co-morbidities.

Symptoms Pain and global disease activity were measured on numerical rating scales (NRSs, range 0–10) with the anchors no pain at all/no symptoms and unbearable pain/extremely severe. Global disease activity was determined according to the question: All symptoms taken into account, what do you think about your condition in the last week? Emotional distress was assessed by the Symptom Checklist-25 (HSCL-25), which is scored 1–4, where 1 is best (not bothered) and 4 extremely bothered. It consists of 25 questions about symptoms of anxiety, depression and other common psychiatric symptoms [14]. The number of painful joints in the body was checked on a figure with a maximum of 68 painful joints.

Disease-specific functioning Disease-specific functioning was assessed by the Western Ontario and McMaster Osteoarthritis Index (WOMAC) [15] and Australian/Canadian Osteoarthritis Hand Index (AUSCAN) (16). WOMAC is developed for patients with hip or knee OA (scored 0–30, where 0 is best). This instrument has been found to be responsive and valid for measuring pain (5 items), stiffness (2 items) and physical function (17 items), and the results can be displayed as one sum score or as three separate subscores. A Likert scale was used with response options none, mild, moderate, severe and extreme, and the score was normalized to a 0–30 scale. AUSCAN is a hand OA disease-specific measure that comprises 15 items relating to hand pain (5 items), stiffness (1 item) and problems with performance of activities (9 items). The results can be presented as a sum score and/or subscores. Response options are none, mild, moderate, severe and extreme (scored 0–10, where 0 is the best) (16).

Health-related quality of life Health-related quality of life was measured by the generic Short Form 36 Health Survey (SF-36) [17], which is a widely used generic instrument that comprises eight health scales [physical functioning (10 items), role limitations due to physical problems (4 items), role limitations due to emotional problems (3 items), bodily pain (2 items), social functioning (2 items), mental health (5 items), vitality (4 items) and general health perceptions (5 items)] that contribute to two higher-order health scales, the Physical Component Summary (PCS) and Mental Component Summary (MCS) summary scores, that give a mean (S.D.) score of 50 [10] based on normative data from the general Norwegian population [18]. The SF-36 is often used to assess health-related quality of life in the general population and in different diseases (scored 0–100, where 100 is best). The English version has been translated and validated in Norwegian with good results [19, 20].

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Statistics We used descriptive statistics to describe the study sample. One-way analyses of variance, t-tests and linear regression analyses were used when comparing the impact of OA localizations. Plots of residuals were assessed. Possible confounding variables specified a priori included age, sex [2] and BMI [21]. These factors were adjusted for in the regression analyses. In the regression model, the group of patients classified as having hand OA was used as the reference group. All data were analysed using SPSS version 17.0, and, when applicable, 95% CI was used.

Results Demographics, localization and symptoms Of the 408 included patients, 86% (n = 351) were women, and the mean age (S.D.) was 63.1 (8.0) years. Analgesics, NSAIDs or other pain medication were used by 32% (n = 132) of patients. Most patients in this sample had one predominant OA localization in hands (n = 270, 66%), hips (n = 33, 8%) or knees (n = 75, 18%), but more generalized disease with two or more affected joint groups was seen in 30 patients (7%). The number of self-reported painful joints was a mean of 10.2 (S.D. 0.7) in hand OA, 7.0 (S.D. 1.1) and 7.1 (S.D. 1.0) in patients with hip and knee OA, respectively, and 13.8 (S.D. 2.4) in patients with generalized disease. Patients with hand OA were significantly older compared with the participants with isolated knee (P < 0.01) and hip (P < 0.046) OA. The BMI in patients with hand OA was significantly lower (P < 0.001) compared with those with isolated knee OA. The mean (S.D.) number of reported co-morbid conditions was 2.1 (1.2). Co-morbidities were similarly distributed through OA localizations and the presence of allergy, hypertension and sciatica were most frequently reported (Table 1). The mean (S.D.) level of pain on an NRS was considerable, with mean scores >5 in all localizations (Table 2). The association between localizations was significantly better in the hand group compared with the hip group, both on pain [NRS (95% CI) 0.99 (0.21, 1.8)] and patient global disease activity [NRS (95% CI) 1.13 (0.4, 1.9)] (Table 3). All localizations scored >1.5 on emotional distress (HSCL-25, 1–4).

Disease-specific functioning Associations between the disease- and localizationspecific instruments AUSCAN for the hands and WOMAC for the hips and knees were significantly worse in their target groups (Table 3). The hand and generalized OA patients had poorer AUSCAN scores, whereas patients with hip and knee OA had poorer WOMAC scores (Table 2). However, patients with hand OA also scored poorly on disease-specific functioning in the lower extremities, with WOMAC values of mean 10.4. Correspondingly, patients with lower extremity OA scored poor on disease-specific functioning in the upper extremities, with AUSCAN values of mean 3.7 in the hip and 3.8 in the knee group (Table 2).

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Rikke Helene Moe et al.

TABLE 1 Demographic characteristics of patients with primary hand, hip, knee or generalized OA Scale, mean (S.D.) (range)

Hand OA (n = 270)

Hip OA (n = 33)

Knee OA (n = 75) Generalized OA (n = 30)

Age (years) Gender, female no. (%) BMI kg/m2 (S.D.) Married/cohabiting (%) Education >12 years (%) Smokers (%) Painful joints (S.D.) Known co-morbidities, no. (%) Stroke Previous cancer Neurological Diabetes Endocrine Hypertension Cardiac event Pulmonary Allergies Sciatica Other chronic inflammatory diseases Total number of co-morbidities, no. (%) 0 1 2 53

63.2 (0.5) 240 (89) 25.9 (0.3) 166 (62) 234 (87) 35 (13) 10.2 (0.7)

61.0 (1.4) 26 (78) 26.3 (0.6) 26 (79) 31 (94) 4 (12) 7.0 (1.1)

60.8 (1.1) 50 (67) 27.7 (0.7) 46 (61) 60 (80) 12 (16) 7.1 (1.0)

63.2 (1.5) 27 (90) 24.1 (0.9) 15 (50) 30 (100) 3 (10) 13.8 (2.4)

7 22 2 14 42 69 24 50 95 68 56

(3) (8) (1) (5) (16) (26) (9) (19) (35) (25) (21)

1 3 1 4 6 12 1 6 13 7 10

(3) (9) (3) (12) (18) (36) (3) (18) (39) (21) (30)

1 4 4 1 9 20 1 12 32 21 14

(1) (5) (5) (1) (12) (27) (1) (16) (43) (28) (19)

0 1 0 0 4 7 0 14 11 8 4

(0) (3) (0) (0) (13) (23) (0) (47) (37) (27) (13)

4 91 54 72

(2) (41) (25) (33)

0 7 7 11

(0) (28) (28) (44)

1 21 13 22

(2) (37) (23) (39)

1 14 8 3

(4) (54) (31) (12)

TABLE 2 Measures of disease impact in people with hand, hip, knee or generalized OA (means and S.D., unadjusted)

Outcome Symptoms (NRS 0–10) Pain Fatigue Stiffness Patient global disease activity HSCL-25 (1–4) Disease-specific functioning AUSCAN sum (0–10) Pain Stiffness Physical WOMAC sum (0–30) Pain Stiffness Physical SF-36 (0–100) Physical functioning Role physical Bodily pain General health perception Vitality Social functioning Role emotional Mental health PCS MCS

Hand OA (n = 270)

Hip OA (n = 33)

Knee OA (n = 75)

Generalized OA (n = 30)

P

5.2 3.9 5.1 4.6 1.6

(0.1) (0.2) (0.2) (0.1) (0.0)

6.1 4.9 5.9 5.7 1.5

(0.4) (0.6) (0.5) (0.4) (0.1)

5.2 4.8 5.0 5.2 1.7

(0.3) (0.3) (0.3) (0.3) (0.0)

5.1 4.5 6.0 5.0 1.6

(0.4) (0.6) (0.4) (0.5) (0.1)

0.09 0.16 0.17 0.03 0.73

5.1 5.0 5.1 5.2 10.4 3.3 4.1 3.0

(0.2) (0.2) (0.2) (0.2) (0.6) (0.2) (0.2) (0.2)

3.7 4.0 3.8 3.3 11.9 3.9 4.5 3.5

(0.4) (0.4) (0.6) (0.5) (1.2) (0.4) (0.4) (0.5)

3.8 3.9 3.8 3.7 13.5 4.8 4.6 4.1

(0.3) (0.3) (0.4) (0.3) (0.8) (0.3) (0.3) (0.3)

5.1 4.9 5.4 4.8 11.6 3.7 4.6 3.3

(0.4) (0.4) (0.4) (0.5) (1.3) (0.4) (0.5) (0.5)