Stratifying healthcare costs using the Diabetes Complication Severity Index☆
Introduction
In Singapore, the prevalence of diabetes mellitus has risen to a 12-year high of 11.3%, from 8.2% in 2004, and 9% in 1998 (EDCD, 2011). The prevalence of diabetes in Singapore was found to be higher than other Asian countries such as Taiwan (5.7%), Japan (7.3%), and Hong Kong (10.2%) (IDF, 2006). Diabetes mellitus is a complex chronic illness that is associated with multiple long-term complications when control of blood glucose and cardiovascular risk factors is poor. This in turn increases health care costs (American Diabetes Association, 2008, Fu and Qiu, 2009, Menzin and Langley-Hawthorne, 2001, Wang and Geiss, 2009), with the global healthcare expenditure expected to total USD376 billion in 2010, and exceeding USD490 billion by 2030 (Zhang et al., 2010). Diabetes complications have been found to account for more than 35% of direct medical expenditures for this disease (Hogan et al., 2003).
Recognizing the burden of diabetes, the healthcare sector has developed various initiatives to improve compliance with pharmacotherapy, preventive screening, and support for self-care for these patients (Aubert and Herman, 1998, Sadur and Moline, 1999). However, cost-intensive disease management efforts become inefficient when they are directed at the entire diabetes mellitus population, including those at low risk of complications. Since managing healthcare costs and reducing morbidity requires targeting “at risk” patients to the appropriate treatment interventions to ameliorate the comorbidities of the disease (Rosenzweig et al., 2002), it is important to develop tools to systematically stratify patients into the different risk categories.
End-organ complications usually develop simultaneously or consecutively in a patient with diabetes rather than independently (Ramsey et al., 1999). The many combinations of diabetic complications add varying degrees of complexity to the overall care of patients, resulting in different utilization of healthcare services and associated costs. Most studies quantified the impact of individual microvascular, and macrovascular complications on healthcare costs (Joyce and Iacoviello, 2004, Nicholas and Brown, 2002). It is also important to note that complications tend to have a multiplicative effect on healthcare costs but studies utilizing traditional linear regression methods tend to assume an additive effect (Clarke et al., 2003). By using an index that summarizes the burden of several complications into a single-value, we can analyze the concurrent risk of higher healthcare costs associated with diabetes complications. Despite these advantages, few studies have reported the use of an overall diabetes complications severity as a risk stratification tool for healthcare costs (Rosenzweig et al., 2002).
A diabetes severity score, derived from automated large administrative and clinical databases, would give researchers and healthcare administrators an easy and reliable method to stratify patients. It would aid in evaluating the short-term direct costs and consequences associated with diabetes interventions. Scoring patients according to the an overall diabetes severity index would enable easy identification of high-risk patients and triage of patients to specific clinical pathways, and the assessment of the effects that each medical condition has on the overall treatment plan and healthcare costs.
Therefore, we aim to construct a validated clinical tool, the Diabetes Complication Severity Index (DCSI), for patients diagnosed with Type 2 Diabetes Mellitus (T2DM), and to determine whether the severity of diabetes complications is associated with healthcare costs in Singapore.
Section snippets
Study design
This is a cohort study of 59,767 T2DM patients who had received care at least twice in one of the 9 National Healthcare Group (NHG) primary care clinics in 2007. We have defined the baseline visit as the last visit made in 2007. All healthcare costs incurred for services provided by the NHG during the two-year follow-up period from Jan 1, 2008 to Dec 31, 2009, were included.
Besides primary care services, NHG also provides inpatient, specialist outpatient, and 24-h emergency through a network of
Results
The study population comprised 59,767 T2DM patients who had received diabetes care at least twice in the same primary care clinic in 2007. Of these, 1336 (2.2%) patients who were lost to follow-up and 2977 (5.0%) patients who died during the study period were excluded. In total, 55,454 (92.8%) patients were included in the analysis.
The clinical and demographic characteristics of the patients are summarized in Table 1. Of the eligible patients, 31,794 (57.3%) had no complications, 11,486 (20.7%)
Discussion
Diabetes mellitus is a chronic condition with many potential macro- and microvascular complications. The amount of healthcare resources and the corresponding cost needed to care for a T2DM patient with no complications compared with another with complications are vastly different. With a severity index such as the DCSI, patients with varying degree of complications severity could be better stratified so as to customise care interventions based on their expected risk. This study analyzed the
Conclusion
This study shows that the DCSI as a diabetes complication severity score of T2DM patients is strongly associated with healthcare costs, even after adjusting for the other medical conditions and factors. It can be used to identify T2DM patients who need more intensive management to prevent or delay the onset of new complications.
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Cited by (21)
Incidence and Prevalence of Microvascular and Macrovascular Diseases and All-cause Mortality in Type 2 Diabetes Mellitus: A 10-year Study in a US Commercially Insured and Medicare Advantage Population
2019, Clinical TherapeuticsCitation Excerpt :The use of diagnosis claims to ascertain microvascular and macrovascular disease in outcomes research studies is well established. One prior study has shown that both the number and severity of diabetes complications (constituents of the Diabetes Complications Severity Index as determined by the presence of ICD diagnosis codes)18,19 were independently associated with increased risk for mortality and hospitalization in a population-based sample of primary care patients with diabetes,20 and have been relied on to estimate costs, and in other types of analyses.21,22 A composite outcome (≥1 claim for any microvascular or macrovascular disease between January 1, 2006, to earlier of December 31, 2015, or death) was also created.
Trends in comorbidity burden and treatment patterns in type 2 diabetes: Longitudinal data from a US cohort from 2006 to 2014
2018, Diabetes Research and Clinical PracticeThe Risk of TB in Patients With Type 2 Diabetes Initiating Metformin vs Sulfonylurea Treatment
2018, ChestCitation Excerpt :However, we used the aDCSI score at baseline as a surrogate marker for hemoglobin A1c and adjusted this variable in multivariate analyses to minimize bias from different DM severities. To verify aDCSI as a practical alternative to hemoglobin A1c, further research is warranted to confirm the relationship between the diabetic complication score and hemoglobin A1c level.38 Second, the reasons for initiating metformin and sulfonylurea treatment may have been dissimilar, although they are the two most frequently used initial drugs for T2DM in Taiwan and are contraindicated in advanced CKD.12,14,17
Stratification strategy for evaluating the influence of diabetes complication severity index on the risk of hospitalization: a record linkage data in Western Australia
2017, Journal of Diabetes and its ComplicationsCitation Excerpt :Costs of health care for people with diabetes with complications have been found to be substantially higher than in those without complications.11,13,14 Recent studies have examined the effect of diabetic complications on health care utilization using the number of complications or DCSI as a continuous variable or a categorical (ordinal) factor in linear regression.13,14,32,33 Although the linear approach is flexible enough to examine the overall pattern of the relationship between the number of complications or DCSI and health care utilization, it may not reflect the underlying probability of the relationship given the conditional nature of subsequent events on prior complication.20
Changes in prevalence of diabetic complications and associated healthcare costs during a 10-year follow-up period among a nationwide diabetic cohort
2015, Journal of Diabetes and its ComplicationsCitation Excerpt :Noteworthy, patients with aDCSI score of 5 or more only accounted for 3.85% of the whole diabetic cohort but consumed highest healthcare costs than other patients. Similar findings were also found in the Wu et al. (2012) study that patients with aDCSI score of 5 or more only accounted for 1.6% of the whole diabetic cohort but consumed 5.9% healthcare costs. These results emphasize the care needs for this specific subgroup of patients with diabetes.
Risk of hospitalization and healthcare cost associated with Diabetes Complication Severity Index in Taiwan's National Health Insurance Research Database
2014, Journal of Diabetes and its Complications
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Conflict of interest and ethics statements: All authors are employees of NHG. This manuscript was prepared without any contract or funding from a sponsor. The authors state that the study has been approved by NHG Domain Specific Review Board (DSRB).