OBJECTIVE To
investigate the relationship between depression and diabetic nephropathy progression
in type 1 diabetes.
<p>RESEARCH DESIGN
AND METHODS Data from 3730 participants without end-stage renal disease at
baseline, participating in the Finnish Diabetic Nephropathy Study, were
included. Depression was assessed in three ways. Depression diagnoses were
obtained from the Finnish Care Register for Health Care. Antidepressant agent
purchase data were obtained from the Drug Prescription Register. Symptoms of
depression were assessed using the Beck Depression Inventory (BDI). Based on
their urinary albumin excretion rate (AER) participants were classified into
those with normal AER, microalbuminuria, and macroalbuminuria. Progression from
normal AER to either microalbuminuria, macroalbuminuria, or end-stage renal
disease; or from microalbuminuria to macroalbuminuria or ESRD; or from
macroalbuminuria to ESRD, during the follow-up period was investigated.</p>
<p>RESULTS Over a mean follow-up period of 9.6
years, renal status deteriorated in 18.4% of the
participants. Diagnosed
depression and antidepressant purchases before baseline were associated with
53% and 32% increased risk of diabetic nephropathy progression, respectively.
Diagnosed depression assessed during follow-up remained associated with
increased risk of disease progression (32%). BDI-derived symptoms of depression
showed no association with the progression, but the total number of
antidepressant purchases modestly reduced the risk [0.989 (0.982–0.997), P=0.008]. Dividing the sample based on
median age, the observations followed those seen in the whole group. However,
symptoms of depression additionally predicted progression in those ≤36.5 years.</p>
<p>CONCLUSIONS<b> </b>Diagnosed depression and
antidepressant purchases are associated with the progression of diabetic
nephropathy in type 1 diabetes. Whether successful treatment of depression
reduces the risk needs to be determined. </p>