Guideline Adherence and Associated Outcomes in the Treatment of Type 2 Diabetes Mellitus Patients With an Incident Cardiovascular Comorbidity: An Analysis Based on a Large German Claims Dataset.

Introduction: According to current guidelines, appropriate drug treatment is the backbone of the effective management of cardiovascular (CV) comorbidities in patients with type 2 diabetes mellitus (T2DM). The main objective of this study was to assess the degree of real-world adherence to these guideline recommendations and to identify whether poor guideline adherence is associated with worse clinical outcomes.

Methods: In this retrospective German claims data analysis (AOK PLUS dataset), patients with T2DM with an incident diagnosis (index date) of ischemic stroke, myocardial infarction, heart failure or coronary artery disease were observed for 12 months between 1 January 2014 and 31 December 2017. We assessed guideline adherence per observed CV disease combination at three levels: "green" if patients received prescriptions of all recommended medications with > 185 defined daily doses (DDDs) per observed patient-year; "yellow" if patients received at least two prescriptions of at least one of the recommended medications; and "red" if patients did not receive at least two prescriptions of at least one of the recommended medications. The impact of the assignment of a patient to one of these three levels on all-cause mortality and CV risk was analyzed based on multivariable Cox regression analyses and reported as adjusted hazard ratios (HRs).

Results: We identified 32,916 patients with T2DM with an incident CV comorbidity (mean age 75.0 years, 54.2% female, Charlson Comorbidity Index [CCI]: 5.5). Observed patients received at least 185 DDDs of the following medication classes in the 12 months before/after the index date: vitamin K antagonists (6%/6%); antiplatelet drugs (9%/27%); novel oral anticoagulants (3%/13%); diuretics (48%/54%); beta blockers (31%/35%); calcium-channel blockers (34%/32%); renin-angiotensin-aldosterone system inhibitors (69%/68%); and lipid-modifying agents (19%/37%). When post-index therapy was compared to guideline recommendations, the level of "guideline adherence" was classified as "green" for 14.4% of the patients, "yellow" for 75.2% and "red" for 10.5%. An assignment of "red" was associated with worse CV outcomes in all analyses. Regarding mortality, in addition to one additional year of age (hazard ratio [HR] 1.04), CCI (HR 1.17), use of insulins (HR 1.25), digitalis glycosides (HR 1.52) and diuretics (HR 1.32), non-adherence to guideline recommendations ("red": HR 6.79; "yellow": HR: 1.30) was a significant predictor for early death, while female gender (HR 0.79), the participation in a disease management program (HR 0.69) and the use of antidiabetics other than insulin (HR 0.74) were generally associated with a reduced risk.

Conclusion: Only a minority of patients with T2DM and an incident CV comorbidity receive a treatment fully adherent with guideline recommendations. This may contribute to high mortality rates in this population in clinical practice.