Health Care Costs Associated with Chronic Kidney Disease in Patients with Type II Diabetes Zita Shiue, MD Internal Medicine, R3 Chief of Medicine Conference October 25, 2011

Outline Background Methods Results Conclusion Future Directions

Background In 2009, it was estimated that the United States had $2.5 trillion in health care expenditures These numbers are projected to continue rising over the next several years Understanding health care costs is an integral part of our job as physicians

Background Chronic kidney disease (CKD) is a growing epidemic, estimated to affect nearly 12% of the country’s population and projected to rise CKD is known to be associated with increased mortality and cardiovascular risk, even at early stages of disease

Background

Patients with CKD are known to utilize health care at high rates and incur more costs (Smith) -Up to 1.9 times more outpatient visits -Up to 4.1 times more use of diabetes medications -Up to 4.2 more inpatient stays -Patients with CKD double the costs of age- matched controls

Background Diabetes is the primary cause of end stage renal disease (ESRD) in the U.S. and is shown to be one of the strongest cost modifiers in patients with CKD In 2007, the number of people diagnosed with diabetes was at least 17.5 million Costs associated with diabetes were estimated at $174 billion by the American Diabetes Association – $116 billion in expenditures – $58 billion in lost productivity – Utilized health care 2.3 more times when compared to patients without diabetes

Background After cardiovascular disease, CKD is the second most costly complication of diabetes Patients with CKD and diabetes cost 1.7 times as much as either alone Patients with diabetes are 12 times more likely to progress to ESRD Once patients are end stage, costs dramatically increase due to dialysis and transplantation

Background Despite the large economic burden created by both diabetes and CKD, there is very little know about the costs at the earlier stages of CKD in patients with diabetes – National Kidney Foundation (NKF) revealed 5 part staging system in 2002 – Most studies have focused on CKD stage 3 and above – Previous studies show that even patients with mild stages of CKD can have increased CVD risk Objective: to evaluate and stratify costs of care at all stages of CKD in a primary care population with Type 2 diabetes

Methods

Participants for the study were recruited as part of the Pathways Epidemiology Study – A prospective population-based cohort sampled from the Group Health diabetes registry Group Health is a non-profit health maintenance organization in Western Washington State 9 of the 30 primary care clinics were selected to be a part of this study for their large population with diabetes and increased diversity

Methods To qualify for the diabetes registry, patients had to fulfill one of the following: – Filled a prescription for insulin or oral hypoglycemic – Two fasting glucose ≥ 126 mg/dl in one year – Two random glucose levels ≥ 200 in one year – Two outpatient diagnoses of diabetes – Any inpatient diagnosis of diabetes

Methods Surveys were mailed to 9064 patients from the diabetes registry – The survey included questions regarding demographics, characteristics of their diabetes, comorbidities, depression Exclusion criteria included: type 1 diabetes, lack of laboratory information regarding kidney function

Methods Primary predictor – Stage of CKD as defined by the National Kidney Foundation stage 1 = eGFR >90mL/min per 1.73m 2 with evidence of proteinuria stage 2 = eGFR mL/min per 1.73m 2 with evidence of proteinuria stage 3 = eGFR mL/min per 1.73m 2 stage 4 = eGFR mL/min per 1.73m 2 stage 5 = eGFR <15 mL/min per 1.73m 2 or on kidney replacement therapy such as dialysis or transplant. – eGFR calculated using MDRD Covariates – age, gender, sex, hypertension, LDL, diabetic complications, education, smoking, body mass index

Methods Costs were evaluated at 6 months – GH assigns budge based costs to every unit of health service rendered Primary Cost Outcomes – Primary and specialty outpatient – Laboratory – Imaging – Emergency – Inpatient – Total Costs – Diabetes related costs - including pharmacy costs (insulin, oral hypoglycemic agents), and laboratory tests (glucose, albumin, hemoglobin A1C (HbA1C)).

Methods Statistical Methods – Descriptive statistics – T-tests for comparisons – Cuzick non-parametric tests for trends – Proportions of costs calculated using individual proportions rather than aggregate proportions

Results

4,938 of 9,064 surveys were returned for a 62% response rate 3,754 people met inclusion criteria Compared to patients in earlier stages of CKD, patients in later stages: – Were older – Had increased number of complications – Less college education – Greater number of people with hypertension

Stage 0 N=498 Stage 1 N= 208 Stage 2 N = 1927 Stage 3 N = 1094 Stage 4 N= 129 Stage 5 N=112 Age, mean (sd)*52.4 (12.3)52.4 (11.5)63.1 (12.1)71.3 (10.3)70.8 (11.3)63.7 (14.1) Sex, M, n (%)239 (48.0)92 (44.2)1079 (56.0)531 (48.5)56 (43.4)63 (56.3) Race, n (%) -Caucasian*341 (69.3)131 (67.5)1524 (81.32)906 (84.8)101 (80.1)86 (77.5) -African Am*68 (13.8)32 (16.3)128 (6.8)67 (6.3)12 (9.5)13 (11.7) -Asian43 (8.7)15 (7.7)148 (7.9)59 (5.5)11 (8.7)8 (7.2) -Other40 (8.1)18 (9.2)74 (4.0)37 (3.5)2 (1.6)4 (3.6) Educ, n (%)*419 (84.3)161 (79.7)1489 (78.4)741 (69.3)83 (64.8)71 (64.0) HbA1c, mean (sd)7.8 (1.6)8.6 (1.9)7.8 (1.5)7.7 (1.4)7.8 (1.5)7.5 (1.6) Compl n (sd)*0.5 (0.8)1.7 (0.9)1.1 (1.1)1.9 (1.4)3.2 (1.1)3.1 (1.5) LDL, mean (sd)*115.0(32.6)115.3 (36.9)111.6 (34.6)109.1(35.2)102.5(33.9)95.8 (30.1) HTN, n (%)*113 (24.0)55 (28.2)750 (41.0)596 (58.1)89 (72.4)78 (72.5) BMI, mean (sd)*32.2 (8.2)33.9 (8.1)31.1 (7.2)30.0 (6.5)31.1 (7.3)29.0 (6.9) Smoking, n (%)*62 (12.5)42 (20.2)157 (8.2)52 (4.8)5 (3.9)9 (8.0)

Results Absolute mean total costs of care increased with worsening stage of CKD Costs at each stage of CKD were significantly increased when compared to stage 0 Increased age was also associated with increased costs African Americans and females were associated with decreased costs

Total and Component Costs

Outpatient Costs

Proportional Costs The proportion of outpatient costs decreased with increasing stage The proportion of inpatient costs increased with increasing stage

Proportional Costs

Inpatient Costs Inpatient costs were rare and few people contributed to the mean costs Mean total costs were recalculated using those that actually incurred costs > 0, – Means were not significantly different by stage However, the number of people contributing did increase with stage

Inpatient Costs

Diabetes Related Care Absolute costs related to diabetes care increased with stage However, the proportion of total costs attributed to diabetes care decreased with stage Diabetes specific ( ) ( ) ( ) ( ) ( ) ( ) Mean costs ($), (sd) Stage 0Stage 1Stage 2Stage 3Stage 4Stage 5

Diabetes Related Care

Conclusion

Conclusions Worsening stage of CKD is associated with significantly increased absolute costs across all cost categories in this Type 2 diabetes population – These results are consistent with previous studies demonstrating increased costs and health care utilization in patient with CKD – This study includes earlier stages of disease and reveals significant increases compared to stage 0 Even “mild” stages of CKD can increase the total cost to the health care system

Conclusions The proportion of inpatient costs increase with stage while the proportion attributed to outpatient costs decreased – Similar to existing studies demonstrating increased hospitalizations in this group – This is due to the increased number of people contributing to inpatient costs at higher stages Absolute costs related to diabetes care increased but the proportion decreased with worsening stage of CKD – This may represent increased utilization of health care on non-direct diabetes care including cardiovascular disease, anemia, ESRD

Discussion In this study, stage 3 CKD was the stage at which the proportions of inpatient, outpatient, and diabetes care changed significantly when compared to stage 0 We often categorize people as chronic kidney disease once they have reached stage 3 However, it may be that prevention of progression to this stage is most important

Discussion As the burden of CKD rises, more research has been devoted to methods of cost control – Angiotensin-converting enzyme inhibitors – Better control of hypertension – Early referral to nephrology – Referral of patients to specialist care group – Early screening – Control of anemia Most of these studies do not involve patients with eGFR >60

Limitations Short follow up time of 6 months eGFR using MDRD at one point in time Costs are CKD plus comorbidities, not isolated Stage 5 analysis included those on dialysis, likely skewing data

Future Directions Would ideally calculate annual costs as well as 5 and 10 years Re-evaluate data using CKD – EPI equation, a better predictor for earlier stages of CKD – Females, African Americans, younger age More cost effectiveness studies, cost saving strategies, even at lower stages of disease

Summary Worsening stage of CKD in patients with diabetes is associated with significantly increased health care costs, even at 6 months This is true even at the earliest stages of disease It is a reflection of increasing comorbidities and health care utilization, especially of inpatient services Efforts should continue to be focused on primary preventive measures to lower late stage costs

References

Thank You Bessie A. Young, MD Courtney Rees Lyles, PhD Group Health Cooperative