Socioeconomic differences in outpatient healthcare utilisation are mainly seen for musculoskeletal problems in groups with poor self-rated health

Aim: To assess whether there are socioeconomic (SES) differences in outpatient visits within groups of comparable morbidity (medical disease and self-rated health) and whether psychosocial factors can explain these differences. Methods: Baseline data for SES, presence of disease, self-rated health (SRH), and psychosocial factors were collected during 2003-04 from 923 men and women aged 45-69 years in southeast Sweden. Outcome data were all registered outpatient healthcare visits to physicians during 2004-08. Cumulative incidences and standardised rate ratios (SSR) were calculated for strata of comparable morbidity for all visits, for visits due to cardiovascular disorders (CVD)/diabetes and for musculoskeletal problems. Results: Low SES was associated with more outpatient visits due to musculoskeletal problems (SRR for education 1.52, 95% CI 1.35-1.73; for occupation 1.40, 95% CI 1.26-1.56) and accentuated in groups with poor SRH. The SES effect was significant for visits to primary care and to hospitals, for men and women, and independent of present disease, SRH, and psychosocial factors. Low SES was significantly associated with more total outpatient visits at primary healthcare centres. In contrast, for outpatient visits due to CVD/diabetes, high SES was related to more visits to hospitals among people with good SRH at baseline. Conclusions: We found a consistent pattern for outpatient visits related to musculoskeletal problems where people with low SES counted more visits and this was most prominent in groups of poor SRH. The results demonstrate the need to apply different morbidity measures when studying inequalities in healthcare utilisation.