A real-world claims data analysis of nearly 200,000 patients with chronic limb-threatening ischaemia (CLTI) showed that female patients were older, underwent vascular procedures less often, and received guideline-recommended drugs less frequently. However, it also highlighted that female sex was associated with better outcomes. The study was recently published in the European Heart Journal.
Authors Lena Makowski (University Hospital Münster, Münster, Germany) et al state that the prevalence of CLTI is increasing, adding that available data often derive from cohorts with various selection criteria. “In the present study,” they communicate, “we included CLTI patients and studied sex-related differences in their risk profile, vascular procedures, and long-term outcomes”.
The researchers analysed 199,953 unselected patients of the AOK Health Insurance Fund—which they describe as the largest public health insurance in Germany—hospitalised between 2010 and 2017. They detail that female CLTI patients were older and more often diagnosed with hypertension, atrial fibrillation, chronic heart failure, and chronic kidney disease, while male patients suffered more frequently from diabetes mellitus, dyslipidaemia, cerebrovascular disease, and chronic coronary syndrome, and were more likely to smoke. Within hospitalised patients, Makowski et al note that females represent the minority (43% vs. 57%; p<0.001).
Writing in the European Heart Journal, Makowski and colleagues report that, during index hospitalisation, women underwent less frequent diagnostic angiographies (67% vs. 70%) and revascularisation procedures (61% vs. 65%; both p<0.001).
Furthermore, they reveal that women received guideline-recommended drugs like statins and antithrombotic therapy less frequently at baseline—35% vs. 43% and 48% vs. 53%, respectively (both p<0.001).
“Interestingly,” the authors underline, “after including age and comorbidities in a Cox regression analysis, female sex was associated with increased overall survival (hazard ratio [HR], 0.95; 95% confidence interval [CI], 0.94–0.96) and amputation-free survival (HR, 0.84; 95% CI, 0.83–0.85; both p<0.001).”
In the discussion of their findings, Makowski et al weigh up various strengths and limitations of their research, noting in particular that their choice of claims database was a key strength of the investigation. They explain that the almost 200,000 lower extremity arterial disease patients included in the study were insured by the AOK Health Insurance Fund, which they note covers almost 32% patients in Germany. Makowski and colleagues add that the AOK consists of 11 independent regional Health Insurance Funds, which covers healthcare nationwide in Germany. However, they highlight that AOK-insured patients have a lower socioeconomic status and higher migration background and presence of cardiovascular risk factors, found in all regions compared with other health insurances. “These differences,” they write, “probably leading to different healthcare supply depending on the regional Health Insurance Fund, can influence the data but demonstrate a nationwide healthcare supply in a heterogeneous patient population”.
The researchers also point to the study design as another strength. “In contrast to randomised trials, observational studies, and registries, the studied health claims data are not subject to selection bias by the sponsor or implementer.”
In addition, the authors communicate that follow-up was good, both in terms of length and data availability. “Patients were included until 2017 and the follow-up phase was until 2018, displaying the current care situation under current guidelines with a longer follow-up to nine years. A very low loss to follow-up was determined, since the change in the health insurance is rather rare, especially in older age groups.”
Moving on to limitations, Makowski et al acknowledge that their analysis is somewhat hindered by the use of health claims data, in that there may be missing information on factors such as clinical status and parameters, the success or failure of interventions, or patient compliance. Moreover, they note that the basis for the analysis was diagnostic codes, which they used for validation reasons. “This means non-billable diagnoses were often not present and thus not included in our analysis,” Makowski and colleagues detail. Another limitation was that differences depending on biological sex (e.g. hormone status), socioeconomic, financial, or health educational aspects could not be included in the analysis.
“[CLTI] should be considered as a multi-organ disease with an ever increasing prevalence and a poor prognosis,” the investigators posit in their conclusion. They stress that CLTI patients “do not receive optimal therapy,” and that this is “more prominent in females”.
