Outpatient healthcare use before and during a long-term sickness absence spell: a register-based follow-up study comparing healthcare use by the length of sickness absence and transition to disability pension in Finland

OBJECTIVES: The objective of the study was to examine outpatient healthcare use before and during a long-term sickness absence (LTSA), and to compare the development of healthcare use between groups defined through LTSA lengths and disability pension (DP) transition. DESIGN: Register-based longitudinal study with five 6-month periods before and after the start of the LTSA spell in early 2016. LTSA groups 1 (N=210) and 2 (N=187) went on to reach the statutory maximum LTSA length, with group 1 transitioning to DP. Group 3 (N=3082) had a shorter LTSA spell. Control group 4 (N=92 921) had no LTSA. SETTING AND PARTICIPANTS: Non-retired individuals aged 20–59, with no LTSA during 2015 (N=96 400) were included from the total population of the city of Oulu, Finland. Register data were linked on LTSA spells and outpatient healthcare use 2013–2018, DP status in 2018, and various covariates. MAIN OUTCOME MEASURES: Negative binomial regression models were used to examine the covariate-adjusted number of healthcare visits, and to examine the association of the LTSA groups with healthcare use before and after the start of LTSA (incidence rate ratios and predicted means). RESULTS: Individuals eventually reaching the maximum LTSA length (groups 1 and 2) had a higher level of healthcare use before the LTSA and especially after the start of LTSA than others. Individuals transferring to DP after the maximum LTSA (group 1) used healthcare the most after the start of LTSA. CONCLUSIONS: The risk for at least 1 year’s disability may be identified by frequent outpatient healthcare use years before LTSA. However, future disability retirees could not be identified through their pre-LTSA healthcare use. Instead, their high use of healthcare after the start of the LTSA was consistent with their increasing health problems leading to retirement.