The longitudinal association between depressive symptoms and initiation of insulin therapy in people with type 2 diabetes in primary care.
OBJECTIVE
To examine whether depressive symptoms are associated with time to insulin initiation in insulin-naïve people with type 2 diabetes in primary care.


METHODS
1,389 participants completed the Edinburgh Depression Scale (EDS) in 2005 and were followed until: 1) insulin therapy was started, 2) death, 3) an oral antihyperglycemic drug (OAD) prescription gap >1 year, 4) last OAD prescription in 2010 or 5) the end of the study (December 31, 2010). Cox regression analyses were used to determine whether there was a difference in time to insulin initiation between people with a low versus a high depression score at baseline, adjusting for potential demographic and clinical confounders, including HbA1c levels.


RESULTS
The prevalence of depression (EDS ≥ 12) was 12% (n=168). After a mean follow-up of 1,597 ± 537 days, 253 (18%) participants had started insulin therapy. The rate of insulin initiation did not differ between depressed and non-depressed participants. People with depression were not more likely to start insulin therapy earlier or later than their non-depressed counterparts (HR=0.98, 95% CI 0.66-1.45), also after adjustment for sex and age (HR=0.95, 0.64-1.42). The association remained non-significant when individual candidate confounders were added to the age- and sex-adjusted base model.


CONCLUSIONS
In the present study, depression was not associated with time to insulin initiation. The hypothesis that depression is associated with delayed initiation of insulin therapy merits more thorough testing, preferably in studies where more information is available about patient-, provider- and health care system factors that may influence the decision to initiate insulin.
CORPS - Center of Research on Psychology in Somatic diseases, Department of Medical and Clinical Psychology, Tilburg University, Tilburg, The Netherlands.
Giesje
G
Nefs
Victor J M
VJ
Pop
Johan
J
Denollet
François
F
Pouwer
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003866:Depressive Disorder / Q000150:complications*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy* / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D007328:Insulin / Q000627:therapeutic use*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data; D011320:Primary Health Care / Q000706:statistics & numerical data*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D013997:Time Factors
D007004:Hypoglycemic Agents; D007328:Insulin