Co-morbidities of patients with knee osteoarthritis

To study the co-morbidities of general practice patients with knee osteoarthritis.

Cross-sectional study.

Two private general practice clinics in Hong Kong.

All patients presenting at the two clinics were screened for osteoarthritis of the knee based on American College of Rheumatology diagnostic criteria. Patients with osteoarthritis then completed a semi-instructed questionnaire.

A total of 455 patients were recruited into the study. Over half (56%) had knee pain plus more than three other diagnostic criteria. Almost all (95%) of the patients with osteoarthritis had no signs of inflammation at the time of screening. Their mean age was 54 years. Overall, 78% of them had at least one musculoskeletal co-morbidity and 82% had at least one non-musculoskeletal co-morbidity. On average they had 3.2 co-morbidities, of which 1.7 were musculoskeletal and 1.5 were non-musculoskeletal. Problems related to the back, upper limbs, neck, and lower limbs were the four most common musculoskeletal co-morbidities, of which neck problems were significantly more common among younger patients (55 years or below) [odds ratio for older to younger patients was 0.62; 95% confidence interval, 0.4-0.9]. The four commonest non-musculoskeletal co-morbidities were cardiovascular, gastro-intestinal, respiratory, and endocrine, of which cardiovascular diseases (odds ratio=8.76; 95% confidence interval, 5.6-13.7), endocrine problems (4.56; 2.8-7.4), and central nervous system diseases (12.74; 1.6-102.8) were significantly likely among older patients (more than 55 years).

General practitioners should be alert to the presence of co-morbidities when managing patients with osteoarthritis of the knee.