Diagnosed depression and purchase of antidepressant medications are associated with an increased risk for diabetic nephropathy progression in patients with type 1 diabetes, according to a recent study.
In an analysis of data from 3730 participants in the Finnish Diabetic Nephropathy Study who did not have end-stage kidney disease (ESKD) at baseline, investigators found that renal status deteriorated in 688 patients (18.4%) over a mean follow-up period of 9.6 years, Aila J. Ahola, MD, of the Folkhälsan Institute of Genetics, Folkhälsan Research Center, and University of Helsinki and Helsinki University Hospital, in Helsinki, Finland, and colleagues reported in Diabetes Care. Diagnosed depression and antidepressant purchases prior to baseline were associated with 53% and 32% increased risks for diabetic nephropathy progression, respectively. Depression diagnosed during follow-up also was significantly associated with a 32% increased risk for progression, but antidepressant purchases during follow-up were not.
Beck Depression Inventory-derived symptoms of depression did not show an association with progression, according to the investigators.
Multivariable analyses showed that history of depression and diagnosis of depression during follow-up were associated with an approximately 1.5- and 1.3-fold increased risk for progression, respectively (P =.015 and P =.006). History of antidepressant purchases was associated with a 1.3-fold increased risk for progression (P =.013).
“To our knowledge, the current study is the first to show the deleterious longitudinal association of depression with the progression of diabetic nephropathy in a sample exclusively comprised of participants with type 1 diabetes,” the authors wrote.
Investigators assessed renal status at baseline based on urinary albumin excretion rate (AER) in at least 2 or 3 timed 24-hour or overnight urine collections. They defined progression as any adverse change from the baseline classification: from baseline normal AER to microalbuminuria, macroalbuminuia, or ESKD; from baseline microalbuminuria to either macroalbuminuria or ESKD; or from baseline macroalbuminuria to ESKD.
Before or after their baseline visit, 511 patients (13.7%) had depression diagnosed and 798 (21.4%) made antidepressant purchases. Women, older individuals, and those with longer diabetes duration were more likely to purchase antidepressants.
Patients whose nephropathy progressed were significantly older than nonprogressors (median 38.6 vs 35.9 years; P =.001) and had a significantly longer diabetes duration (median 24.3 vs 19.5 years; P <.001). Progressors also had a significantly greater proportion of individuals with a history of antidepressant medication purchases (14.8% vs 11.6%; P =.024) and antidepressant purchases during follow-up compared with nonprogressors (29.9% vs 23.7%; P =.001), Dr Ahola and colleagues reported.
The study found that a higher number of antidepressant purchases over time had a small but significant negative association with progression, a finding suggesting a presence of a protective effect, according to the investigators. “The mechanisms behind this association are not known, but it is possible that, should regular antidepressant usage alleviate the symptoms of depression, their use would thereby help affected individuals to better take care of their diabetes.”
“A major strength of this study is that the sample consists solely of adults with type 1 diabetes, unlike most of the previous studies, which have been conducted either in individuals with type 2 diabetes or in samples pooling data from participants with type 1 and type 2 diabetes.”
With regard to study limitations, the authors acknowledged that although they adjusted for a large number of well-known risk factors in their analyses, they cannot exclude the possibility of residual confounding due to unknown variables. “Also, although the study was longitudinal, causality between depression and progression of diabetic nephropathy cannot be ascertained based on our observations.”
Ahola AJ, Harjutsalo V, Forsblom C, et al. Depression is associated with progression of diabetic nephropathy in type 1 diabetes. Published online November 11, 2020. Diabetes Care. doi:10.2337/dc20-0493