Has socioeconomic equity increased in somatic specialist care: a register-based cohort study from Finland in 1995–2010

BACKGROUND: Equal access to health care according to need is an important goal for health policy in Finland. Earlier research in Finland and elsewhere has mainly been cross-sectional, but the results have implied that the goal has not been fully realised in somatic specialist hospital care. This study examines trends in socioeconomic equity in use of somatic specialist hospital care. METHODS: We used register data on somatic specialist hospital admissions among 25–84 year-old persons in Finland in 1995–2010 with individually linked register-based socio-demographic information. We calculated age-standardised admission rates per 100,000 person years by income, examined risk ratios using Poisson regression models and computed concentration indices separately for men and women. Linear trends in the socioeconomic distribution of admissions and surgical procedures were estimated with linear regression models for annual concentration indices. RESULTS: Overall, use of somatic specialist hospital care decreased steadily throughout the study period. A stepwise inverse income pattern was found in hospitalisation risk and in non-surgical admissions: the lower the income group, the higher the risk. The relative admission risk was approximately two times higher in the lowest income group compared to the highest among both genders. Few differences were found in surgical admissions. Income group differences remained stable in hospitalisations and surgical admissions, but increased in non-surgical admissions during the study period. An inverse pattern of increasing operation rates with decreasing income was found in primary hip and knee replacement operations, and in lower limb amputations. A similar pattern emerged during the study period in coronary revascularisations. There were no differences were found in lumbar fusion or lumbar disc operations, prostatectomies or appendectomies. Income group differences in hysterectomies disappeared during the study period. CONCLUSIONS: While the results of the current study suggest that use of somatic specialist care declined in line with improving population health in 1995–2010, the increase of socioeconomic health differentials was only partly reflected in the distribution of somatic specialist hospital care. Further research is needed to evaluate the need to improve use and content of specialised hospital care among the low-income groups in order to improve equity in health care.