Association of kidney function impairment with healthcare service utilisation in individuals with type 2 diabetes: an observational follow-up study in primary care

Type 2 diabetes (T2D) causes a major burden on healthcare and is a leading cause of chronic kidney disease (CKD). While the healthcare service utilisation of individuals with CKD in speciality clinics and the high costs of renal replacement therapy have been widely studied, the burden of kidney function impairment on primary healthcare remains understudied. In this study, we aimed to examine the association of kidney function impairment with primary healthcare service utilisation in individuals with T2D. This observational follow-up study consisted of 4773 individuals with T2D treated in the municipal Rovaniemi healthcare centre, Rovaniemi, Finland between 2011 and 2019 (mean age 70.9 years; 53.5% males). The mean follow-up period was 5.6 years. Substantial kidney function impairment was defined as a reduction of 25% or more in the estimated glomerular filtration rate (eGFR) over the follow-up and was contrasted to non-substantial kidney function impairment (eGFR reduction of less than 25%). Primary healthcare service utilisation included planned diabetes appointments, unplanned general practice [GP] appointments, other GP contacts (digital, phone or letter), unplanned nurse appointments, other nurse contacts (digital, phone or letter) and inpatient days in the healthcare centre that occurred during the follow-up. The association between kidney function impairment and primary healthcare service utilisation was studied with negative binomial regression models adjusted for potential confounding factors. Substantial kidney function impairment occurred in 12.9% of the study population. Compared to non-substantial kidney function impairment, substantial kidney function impairment associated with increased primary healthcare service utilization when measured with planned diabetes appointments (adjusted incidence rate ratio [aIRR] 1.18, 95% confidence interval [CI] 1.09–1.28), other GP contacts (aIRR 1.38, 95% CI 1.57–1.84), unplanned nurse appointments (aIRR 1.19, 95% CI 1.02–1.24), and inpatient days in the healthcare centre (aIRR 1.20, 95% CI 1.10–1.45). Kidney function impairment in individuals with T2D was associated with an increase in primary healthcare service utilisation in several measured categories. This further underlines the importance of prevention and prompt treatment of CKD in individuals with T2D to reduce the burden on primary healthcare.