Does antidepressant medication use affect persistence with diabetes medicines?

PURPOSE: This study aimed to examine the effect of antidepressant use on persistence with newly initiated oral antidiabetic medicines in older people. METHODS: A retrospective study of administrative claims data from the Australian Government Department of Veterans' Affairs, from 1 July 2000 to 30 June 2008 of new users of oral antidiabetic medicines (metformin or sulfonylurea). Antidepressant medicine use was determined in the 6 months preceding the index date of the first dispensing of an oral antidiabetic medicine. The outcome was time to discontinuation of diabetes therapy in those with antidepressant use compared with those without. Competing risks regression analyses were conducted with adjustment for covariates. RESULTS: A total of 29,710 new users of metformin or sulfonylurea were identified, with 7171 (24.2%) dispensed an antidepressant. Median duration of oral antidiabetic medicines was 1.81 years (95% CI 1.72­1.94) for those who received an antidepressant at the time of diabetes medicine initiation, by comparison to 3.23 years (95% CI 3.10­3.40) for those who did not receive an antidepressant. Competing risk analyses showed a 42% increased likelihood of discontinuation of diabetes medications in persons who received an antidepressant (subdistribution hazard ratio 1.42, 95% CI 1.37­1.47, p < 0.001). CONCLUSIONS: The results of this large population-based study demonstrate that depression may be contributing to non-compliance with medicines for diabetes and highlight the need to provide additional services to support appropriate medicine use in those initiating diabetes medicines with co-morbid depression.

Major bleeding risk associated with warfarin and co-medications in the elderly population.

PURPOSE: Warfarin management in the elderly population is complex as medicines prescribed for concomitant diseases may further increase the risk of major bleeding associated with warfarin use. We aimed to quantify the excess risk of bleeding-related hospitalisation when warfarin was co-dispensed with potentially interacting medicines. METHODS: A retrospective cohort study was undertaken over a 4-year period from July 2002 to June 2006 to examine bleeding risk associated with medications co-administered in patients taking warfarin using an administrative claims database from the Australian Department of Veterans' Affairs. All veterans aged 65 years and over who were new users of warfarin were followed until death or study end. Risk of bleeding was assessed using a Poisson GEE model adjusting for age, gender, socioeconomic status, co-morbidity index, previous bleeding related hospitalisations and indicators of health service use. RESULTS: Overall, 17661 veterans who used warfarin at any time during the study period were included. The overall incidence rate of bleeding-related hospitalisations was 4.1 (95% CI 3.7-4.6) per 100 person-years in veterans who were not receiving potentially interacting medicines. Bleeding-related hospitalisation rates were significantly increased when warfarin was co-prescribed with low-dose aspirin (Adjusted rate ratio (AdjRR) 1.44, 95% CI 1.00-2.07), clopidogrel (AdjRR 2.23, 95% CI 1.48­3.36), clopidogrel with aspirin (AdjRR 3.44, 95% CI 1.28-9.23), amiodarone (AdjRR 3.33, 95% CI 1.38­8.00) and antibiotics (AdjRR 2.34, 95% CI 1.55-3.54). CONCLUSIONS: Models assessing bleeding risk with warfarin should take account of the range of potentially harmful medicine combinations used in elderly people with comorbid conditions.

Comorbid diabetes and COPD: impact of corticosteroid use on diabetes complications.

OBJECTIVE: To identify if there is a dose-dependent risk of diabetes complications in patients treated with corticosteroids who have both diabetes and chronic obstructive pulmonary disorder (COPD). RESEARCH DESIGN AND METHODS: A retrospective study of administrative claims data from the Australian Government Department of Veterans' Affairs, from 1 July 2001 to 30 June 2008, of diabetes patients newly initiated on metformin or sulfonylurea. COPD was identified by dispensings of tiotropium or ipratropium in the 6 months preceding study entry. Total corticosteroid use (inhaled and systemic) in the 12 months after study entry was determined. The outcome was time to hospitalization for a diabetes-related complication. Competing risks and Cox proportional hazard regression analyses were conducted with adjustment for a number of covariates. RESULTS: A total of 18,226 subjects with diabetes were identified, of which 5.9% had COPD. Of those with COPD, 67.2% were dispensed corticosteroids in the 12 months from study entry. Stratification by dose of corticosteroids demonstrated a 94% increased likelihood of hospitalization for a diabetes complication for those who received a total defined daily dose (DDD) of corticosteroids≥0.83/day (subhazard ratio 1.94 [95% CI 1.14-3.28], P=0.014), by comparison with those who did not receive a corticosteroid. Lower doses of corticosteroid (<0.83 DDD/day) were not associated with an increased risk of diabetes-related hospitalization. CONCLUSIONS: In patients with diabetes and COPD, an increased risk of diabetes-related hospitalizations was only evident with use of high doses of corticosteroids. This highlights the need for constant revision of corticosteroid dose in those with diabetes and COPD, to ensure that the minimally effective dose is used, together with review of appropriate response to therapy.

Influence of comorbidities on therapeutic progression of diabetes treatment in Australian veterans: a cohort study.

BACKGROUND: This study assessed whether the number of comorbid conditions unrelated to diabetes was associated with a delay in therapeutic progression of diabetes treatment in Australian veterans. METHODOLOGY/PRINCIPAL FINDINGS: A retrospective cohort study was undertaken using data from the Australian Department of Veterans' Affairs (DVA) claims database between July 2000 and June 2008. The study included new users of metformin or sulfonylurea medicines. The outcome was the time to addition or switch to another antidiabetic treatment. The total number of comorbid conditions unrelated to diabetes was identified using the pharmaceutical-based comorbidity index, Rx-Risk-V. Competing risk regression analyses were conducted, with adjustments for a number of covariates that included age, gender, residential status, use of endocrinology service, number of hospitalisation episodes and adherence to diabetes medicines. Overall, 20,134 veterans were included in the study. At one year, 23.5% of patients with diabetes had a second medicine added or had switched to another medicine, with 41.4% progressing by 4 years. The number of unrelated comorbidities was significantly associated with the time to addition of an antidiabetic medicine or switch to insulin (subhazard ratio [SHR] 0.87 [95% CI 0.84-0.91], P<0.001). Depression, cancer, chronic obstructive pulmonary disease, dementia, and Parkinson's disease were individually associated with a decreased likelihood of therapeutic progression. Age, residential status, number of hospitalisations and adherence to anti-diabetic medicines delayed therapeutic progression. CONCLUSIONS/SIGNIFICANCE: Increasing numbers of unrelated conditions decreased the likelihood of therapeutic progression in veterans with diabetes. These results have implications for the development of quality measures, clinical guidelines and the construction of models of care for management of diabetes in elderly people with comorbidities.