Long-term Impact of CVD and CKD on Life Expectancy and on Direct Medical Costs in Patients with Diabetes

Background

Nearly 20-40% of diabetes patients suffer with comorbid cardiovascular disease (CVD) and varying severity of chronic kidney disease (CKD). Such comorbidities not only increase the economic burden but also increase the risk of mortality in diabetes patients. Nevertheless, the impact of CVD and CKD on Life expectancy followed by cost in diabetes patients has not been completely explored till date. Correct estimation of the burden of CVD and CKD may help understand the actual impact of these diseases on life expectancy and the long-term medical costs.

Aim

To determine the long-term impact of CVD and CKD individually and jointly on mortality risks, life expectancy, and direct medical costs in patients with diabetes

Patient Profile

• Adults patients with diabetes
• Based on the varying combination of CVD and CKD [moderate CKD; estimated glomerular filtration rate (GFR): 30–59 mL/min/ 1.73 m², severe CKD; eGFR: <30 mL/min/1.73 m²], patients were stratified into 12 groups as follows:

Methods

Study Design

• Population-based retrospective cohort study

Outcomes

Primary Outcome

• All-cause mortality

Secondary Outcomes

• Annual direct medical cost
• Life expectancy

Assessments

• The association between various disease status group and mortality was determined through subgroup analyses stratified by the following variates at baseline
  • Gender (male/female)
  • Age (<65 years, ≥65 years)
  • Smoking status (nonsmoker, smoker)
  • Duration of diabetes (<5 years, ≥5 years)
  • Body mass index (BMI; <27.5 kg/m², ≥27.5 kg/m²)
  • Blood pressure [systolic blood pressure (SBP) <130 mmHg and diastolic BP (DBP) <80 mmHg, SBP/DBP ≥130/80 mmHg)
  • Glycosylated hemoglobin (HbA1c; <7%, ≥7%)
  • Low-density lipoprotein-cholesterol (LDL-C; <100, ≥100)
  • The use of antihypertensives (no/yes)
  • The use of antidiabetics (no/yes)
  • The use of lipid lowering drugs (no/yes)

Follow-up

• Median follow-up: 8.5 years (1.6 million patient-years)

Results

• A total of 208,792were included in the study, of these, 5.7% (n=11,922) had stroke, 5.1% (n=10,736) had heart disease, 5.4% (n=11,367) had moderate CKD, and 0.5% (n=1,114) had severe CKD.
• Of the entire study population, 16.8% (n=35,139) had one condition (stroke, heart disease, or CKD), 3.3% (n=6,981) had two conditions, and 0.4% (n=801) had three conditions.
• A total of 50,154 deaths were recorded during the median follow-up of 8.5 years. The risk of mortality for patients with only a single condition among heart disease, stroke, and moderate CKD was similar.
• Patients with one, two, and all three conditions (consisting of stroke, heart disease, and moderate CKD) had a 1.75 times, 2.63 times, and 3.58 times greater risk of mortality, respectively, as compared with patients without CVD or CKD, indicating an independent and individually additive effect for any disease combination. Patients with severe CKD alone or in combination of stroke and heart disease had much higher mortality as compared with those without severe CKD ± other complications.
• Similarly, patients with one, two or all three conditions had a 2.91-, 3.90-, and 3.88-fold higher annual public health care costs, respectively as compared to the patients without any of these diseases. Patients with severe CKD alone or in a combination with stroke and heart disease had much higher medical costs compared with those without severe CKD ± other complications
• The life expectancy reduced greatly with increasing number of conditions, particularly in younger patients, though elderly patients also had a substantial reduction in life expectancy. Thus, for a 40-year-old with one, two, and three conditions, the reduction in life expectancy was 20, 25, and 30 years for males and 25, 30, and 35 years, respectively, for females. Patients with severe CKD alone or in combination with stroke and heart disease had even more prominent reduction in life expectancy.

Conclusions

• Heart diseases, stroke, moderate CKD individually had an additive impact on the risk of mortality in patients with diabetes. Importantly, this impact was non-overlapping for any combination of these conditions.  
• The mortality risk associated with severe CKD was larger than the combined impact of stroke, heart diseases, and moderate CKD.
• A similar trend was also observed for the annual medical costs, associated with heart disease, stroke and CKD.
• Increasing number of conditions was associated with a significant reduction in life expectancy, particularly in younger patients.
• Long-term management and prevention of CVD and CKD is therefore crucial in patients with diabetes.

Diabetes Care. May 26, 2020 (published Online); DOI: 10.2337/dc19-2137.