Change in medical practice over time? A register based study of regional trends in hysterectomy in Finland in 2001-2018

A persistent research finding in Finland and elsewhere has been variation in medical practices both between and within countries. Variation seems to exist especially if medical decision making involves discretion and the best treatment cannot be identified unambiguously. This is true for hysterectomy when performed for benign causes. The aim of the current study was to investigate regional trends in hysterectomy in Finland and the potential convergence of rates over time. We used hospital discharge register data on hysterectomies performed, diagnoses, age, and region of residence to examine hospital discharges for women undergoing hysterectomy in 2001–2018 among total female population aged 25 years or older in Finland. We examined hysterectomy rates among biannual cohorts by indication, calculated age-standardised rates and used multilevel models to analyse potential convergence over time. Altogether 131,695 hysterectomies were performed in Finland 2001–2018. We found a decreasing trend, with the age-adjusted overall hysterectomy rate decreasing from 553/100,000 person years in 2001–2002 to 289/100,000 py in 2017–2018. Large but converging regional differences were found. The correlations between hospital district intercepts and slopes in time ranged from − 0.71 to − 0.97 (p < 0.001) suggesting diminishing variation. Our findings demonstrate that change in hysterectomy practices and more uniformity across regions are achievable goals. Regional variation still exists suggesting differences in medical practices.