Background: Patients with type 2 diabetes (T2D) are at higher risk of developing various complications of different severity, but the sequential order of occurrence is not clear.
Objectives: To determine clinical progression pathways of patients with T2D.
Methods: We performed a systematic evaluation of healthcare data sources converted to the OMOP common data model using OHDSI tools. The study included adults with newly identified T2D (index event) determined by diagnosis and treatment codes, between 2001 and 2019. At least one year of database history was required before the index event. Subsequently, we tracked the temporal sequence of occurrence of specific conditions during the observation period. The conditions considered relevant to patients with T2D included: chronic kidney disease (CKD), diabetic retinopathy (DR), diabetic neuropathy (DNeu), coronary heart disease (CHD), cerebrovascular disease (CeVD), heart failure (HF) and peripheral artery disease (PAD). Data sources included in the study are: MarketScan commercial claims and medicare combined (MS), Optum Claims, and OPTUM EMR from the US and CPRD from the UK. Once the sequences were determined, we used a modified Txpath tool to produce sunburst plots stratified by database, and calendar year. To allow a sufficiently informative dataset, we selected patients with at least 2 years of observation period after the index date. A sensitivity analysis with the full dataset was performed.
Results: We identified 181,495 patients with incident T2D in CPRD during the study period, 251,074 in OPTUM and 612,782 in MS. Between 53-57% were male and aged between 5560 years at baseline, being younger in MS. Charlson’s index was 1.52 in CPRD, 2.55 in OPTUM and 2.07 in MS. The most common comorbidity at baseline was hypertension with a prevalence of 33% in CPRD, 71% in OPTUM and 64% in MS. In CPRD, nearly half of patients developed an additional complication, 51.4% in OPTUM and 40.7% in MS. The most common complication during the study period following T2D diagnosis in CPRD was DR (23.1%) followed by CKD (12.1%) and CHD (4.5%). In OPTUM, PAD was the most frequent complication after T2D (11%), then CKD (10%), CHD (9.9%), and DNeu (7.2%). Lastly, in MS, PAD (9.0%), then CHD (9.4%), CeVD (7.0%), and CKD (5.5%) were the most common complications after T2D. In CPRD we observed secular changes in some of these complications over time, with an increase in DR and a decrease in CKD coding.
Conclusions: Patients with incident T2D are at high risk of suffering multiple clinical complications over a long period of time, however the sequential order of such conditions is heterogeneous across databases. Understanding the complex clinical pathways among patients with T2D may help optimize healthcare delivery.
