The disease process and utilization of health services in rheumatoid arthritis: the relative contributions of various markers of disease severity in explaining consumption patterns.

OBJECTIVE: To examine the predictive ability of a wide array of measures of disease severity in explaining Dutch and German patterns of health services utilization during a 2-year period.

METHODS: Slightly over 200 rheumatoid arthritis (RA) patients, 136 from a Dutch and 98 from a German outpatient clinic, supplied information on symptom and functional status, global health, and emotional and social functioning at baseline. The patients' rheumatologists provided clinical assessments of functional grade and disease activity. A questionnaire mailed twice at 12-month intervals was the source of retrospective information on physician consultations, hospitalization, and referrals for surgery and physical therapy during the previous period. Major determinants of use were studied with multivariate analyses.

RESULTS: German patients reported more frequent physician contacts than Dutch patients, but the volume of surgery, hospital admissions, and referrals for physical therapy did not differ between the two countries. In a hierarchical regression, the consultation rate was directly associated with pain quality and global health. Markers of RA progression were related to surgery, and the latter to volume of in-hospital care. Fatigue severity and physical disability predicted referrals for physical therapy. Patient self-management activities were only weakly associated with disease severity variables.

CONCLUSION: The activity and damage components of RA were related to the separate components of total health service utilization. Disease activity was the prime determinant of physician services used, and RA progression the determinant of surgical interventions and hospitalization.