The Human and Economic Burden of Diabetes and Its Comorbidities

An examination of the economic burden of diabetes finds every comorbidity related to diabetes causes life expectancy to plummet and medical costs to soar.

Projections indicate that by the year 2045, there will be 693 million diabetes cases throughout the world, a steady increase from the 451 million cases in 2017. Along with a decrease in life expectancy, this disease growth will cause healthcare costs to rise much higher than the estimated $600-1200 billion (in US dollars) annual global cost of diabetes in 2014. To be prepared for future challenges, patients and healthcare workers need to be aware of the higher mortality rates and increased costs of treatment associated with diabetes, which rise even more when combined with comorbidities such as cardiovascular disease (CVD) and chronic kidney disease (CKD).  A May 2020 Hong Kong-based study published in the journal Diabetes Care quantified the effects of diabetes and related comorbidities with healthcare costs and life expectancy.

This retrospective cohort study included 208,792 patients with diabetes whose records were provided by the Hong Kong Hospital Authority, which manages all public sector hospitals and primary care clinics in Hong Kong. January 1, 2008, to December 31, 2010, records of patients 18 years of age or older with a definite diagnosis of diabetes were analyzed for the study. Subjects were divided into twelve groups by disease composition of comorbidities in addition to diabetes: stroke, heart disease (including heart failure, coronary artery disease), moderate CKD (defined as eGFR ≥ 30 mL/min/1.73m_­² and <60 mL/min/1.73m_­²), and severe CKD (defined as eGFR <30 mL/min/1.73m_­²). Of all patients, 16.8% had one comorbidity, 3.3% had two comorbidities, and 0.4% had three comorbidities.  The most common comorbidity was stroke (5.7%), followed by moderate CKD (5.4%), then heart failure (5.1%). Severe CKD was only reported in 0.5% of the patient population. Based on conditions, patients were stratified into the following groups:

1. Reference Group – no comorbidities (diabetes only)
2. Stroke
3. Heart disease
4. Moderate CKD
5. Severe CKD
6. Stroke and heart disease
7. Heart disease and moderate CKD
8. Stroke and moderate CKD
9. Stroke and severe CKD
10. Heart disease and severe CKD
11. Stroke, heart disease, and moderate CKD
12. Stroke, heart disease, and severe CKD

The study’s primary outcome was all-cause mortality, for which data was obtained from the Hong Kong Death Registry (HKDR). This official government entity records the deaths of all Hong Kong citizens. Secondary outcomes for this study were life expectancy and the annual direct medical cost. Total medical costs included hospital inpatient services, emergency services, accident services, and general and specialist outpatient services such as clinical psychologists, dietitians, and physical therapists. In addition, the Hong Kong Hospital Authority provided data for the frequency of health service use, and the cost of those services was calculated from guidelines published by the government of Hong Kong.

Mortality rates were calculated at a median 8.5-year follow-up with data from the HKDR and reported as the incident rate in cases per 100 person-years. The cost was quantified as the estimated annual public-directed medical cost. Data showed that the mortality incidence rate increased with the addition of each comorbidity, particularly severe CKD. The cost of treatment was also higher as the number of comorbidities increased, with severe CKD being the most significant contributor. The reported data is as follows:

A strength of this study was the large study population of over 200,000 patients and the fact that the data was validated by government entities that have access to the records of multiple hospital organizations and records of death. However, the study’s narrow demographic was a limitation, as the population was solely citizens of Hong Kong. Thus, it may not be generalizable to more diverse populations, such as the United States. Furthermore, how the Hong Kong government determined healthcare costs may not be the same in other countries. Another limitation of the study is that researchers had no control or record of patient medication compliance due to the retrospective nature, which is another critical factor in disease management. Researchers also had a problem accessing ICD-9 classifications of diseases when searching the databases, so ICPC-2 codes were utilized, which caused type 1 diabetes patients to be included in the study. Despite its limitations, this study provided a broad overview of the economic and human costs of diabetes and its comorbidities.

Practice Pearls:                          

• Mortality rates and treatment costs increase with the number of comorbidities a patient with diabetes has.
• Severe chronic kidney disease has the most significant impact on mortality and cost of treatment in patients with diabetes.
• Preventing the development of diabetes-related comorbidities is critical for decreasing patient mortality and minimizing economic burden & healthcare costs.

Reference for “The Human and Economic Burden of Diabetes and Its Comorbidities”:
Wan, Eric Yuk Fai, et al. “The Impact of Cardiovascular Disease and Chronic Kidney Disease on Life Expectancy and Direct Medical Cost in a 10-Year Diabetes Cohort Study.” Diabetes Care, 2020.

Sameen Khan, Pharm.D. Candidate, USF College of Pharmacy