The American Journal of Managed Care May 2009
The Effectiveness of Diabetes Care Management in Managed Care
Care management patients experienced slightly greater improvements in CVD risk factor control than a set of matched controls. Both populations showed significant improvement over time.
Objectives: To evaluate the effectiveness of the diabetes care management (CM) program in Kaiser Permanente Northern California (KPNC) by determining the proportion of enrollees that met program entry criteria and by comparing intermediate outcomes trajectories of enrollees versus similar patients who did not receive CM.
Study Design: Observational study with propensity score matching of CM patients to control subjects.
Methods: Care management program entry criteria were assessed for 179,249 adult patients with diabetes mellitus in 2003 and were compared between CM and non-CM patients in that year. Propensity score matching was used to match CM patients with comparable non-CM controls. Preprogram and postprogram glycosylated hemoglobin (A1C), low-density lipoprotein cholesterol (LDL-C), and systolic blood pressure levels, as well as medication adherence, and treatment intensification rates of CM patients, were compared for enrollees versus controls.
Results: Sixteen percent of CM patients were ineligible by program entry criteria. Small but statistically significant differences in A1C and LDL-C levels favoring CM patients were observed during 15 months of postprogram follow-up. Care management patients were more likely to receive treatment intensification for poorly controlled hyperglycemia, hyperlipidemia, and hypertension. Improvements in all 3 cardiovascular risk factor levels were observed for all KPNC patients with diabetes regardless of CM participation.
Conclusions: Eligibility guidelines for diabetes CM were not strictly adhered to in this program. Nevertheless, in a population with improving risk factor control, patients entering CM experienced slightly greater improvement.
(Am J Manag Care. 2009;15(5):295-301)
This study of the diabetes care management program in Kaiser Permanente Northern California examined fidelity to program entry criteria and compared intermediate outcomes trajectories of program enrollees versus similar patients who did not receive care management. Findings include the following:
- Sixteen percent of care management patients in 2003 did not meet program eligibility criteria.
- Thirty-three percent of patients who did not receive care management met program eligibility criteria.
- Care management patients showed small improvements in control of glycosylated hemoglobin and low-density lipoprotein cholesterol levels compared with matched controls.
- Significant improvements in all cardiovascular disease risk factor levels were observed for all patients with diabetes regardless of participation in care management.
Kaiser Permanente Northern California (KPNC) implemented a large-scale primarily nurse-led diabetes CM program beginning in 1999. More than 150 diabetes nurse care managers offered intensive counseling on medication management (including appropriate titration) and adherence, diet, and lifestyle to patients with diabetes referred to CM by their primary care physician. Care management was designed to help provide additional individualized patient support beyond primary care for improving self-management and cardiovascular disease (CVD) risk factor control. Control of glycemia was a central focus from the program’s inception; emphasis on blood pressure and lipid control was
added in later years. This program was designed to treat patients for 3 to 6 months and then to place the patients back into the primary care system once (ideally) CVD risk factors and self-management behaviors had improved.
The objectives of this study were 3-fold: (1) to describe the population of patients enrolled in this program, (2) to assess correspondence of program enrollment with stated entry criteria, and (3) to evaluate program effectiveness for improving A1C level, LDL-C level, systolic blood pressure (SBP), medication adherence, and appropriate treatment intensification.
This study was developed and approved by the steering committee of the Translating Research in Action for Diabetes (TRIAD) study15 and was conducted in KPNC, which is 1 of 6 TRIAD translational research centers. As an integrated healthcare delivery system, KPNC provides comprehensive medical care to a diverse population of approximately 3.2 million members in Northern California. Patients with diabetes were selected for the study from the KPNC diabetes registry19 if they were identified as having diabetes before December 31, 2002; were aged 20 to 85 years as of January 2003; and were continuously enrolled with an active drug benefit in January 2003. A small number of patients (n =
2609) who were likely to have type 1 diabetes mellitus (age <40 years as of January 1, 2003, and taking insulin only) were excluded. Initial SBP and A1C, LDL-C, and albumin levels for CM patients and for patients with diabetes not in CM were compared using the first value for 2003 found in the registry database. Patients were identified as CM participants if they had a diabetes CM entry date between January 1, 2003, and December 31, 2003, in the automated “Alert Note” CM database and had at least 1 day of enrollment in the program. Official eligibility criteria for the KPNC CM program state that patients entering diabetes CM should meet 1 or more of the following criteria: (1) an A1C level of at least 8.5%, (2) an albumin level exceeding 3.0 g/dL, or (3) a diabetes-related hospitalization or emergency department (ED) visit. All patients with diabetes were assessed for whether they met CM program entry criteria between July 1, 2002, and December 31, 2003.
Matching CM Patients to Control Subjects
To assess program effectiveness for improving SBP and A1C and LDL-C levels, as well as medication adherence and treatment intensification rates, the study included all CM patients who had been identified as having diabetes since at least December 2001 and who had been enrolled continuously with an active drug benefit from January 2002 through December 2005. These selection criteria allowed assessment of long-term intermediate outcomes and medication adherence before entering and after leaving CM. Because program participants could potentially differ from nonparticipants on a number of patient-level characteristics such as age or disease burden (as well as possibly the characteristics of their referring primary care physicians), the study used propensity score matching.20 This matching allowed for comparison of CM patients’ outcomes with those of similar patients who did not enter CM, while effectively controlling for differences in their baseline characteristics.20 Matched control subjects were selected from registry members who met the diabetes duration, health plan membership, and benefit criteria but who did not enter CM during 2003. For matching, all eligible patients were first assigned a propensity score (probability range, 0-1) for entering CM using logistic regression analysis and including the following predictors: age, sex, race/ethnicity, A1C level, albumin level, whether the patient had a diabetes-related hospitalization or ED visit in the prior year, comorbidity score (DxCG, Inc, Boston, Massachusetts) derived from hospital and ambulatory diagnoses during 2002,21 use of insulin, number of primary care visits in 2003, number of patients with diabetes in the patient’s primary care physician panel in 2003, and percentage of patients with diabetes in a primary care physician’s panel referred to CM in 2003. These variables were chosen because they reflected the official entry criteria for entering CM (and were likely to influence whether patients were referred into the program) or because they measured patient-level or physicianlevel characteristics that were likely to influence program entry. Each CM patient was matched to the control having the closest propensity score possible who also had an A1C reading during the quarter of 2003 in which the CM patient entered the program.
Adherence to Medication Regimens
Adherence to diabetes, hypertension, and hyperlipidemia medication regimens for 12 months before and after CM was calculated separately for each condition among CM patients and matched controls using KPNC prescription databases. For each medication class, the proportion of days between first and last prescription fills in the 12-month periods for which the patient did not have medication available was determined.22,23 Adherence was first calculated separately for each medication class and then was combined across all medications prescribed for a single condition, weighing each by the interval from first to last prescription fill in the period. Consistent with prior findings in this setting,24 poor adherence for each condition was defined as a weighted nonadherence measure of at least 20% across all medications prescribed for the condition.
Treatment intensification during 12 months following the start of CM was assessed for each CM patient and his or her matched control using prescription fills during 3 months before and 3 months after the first above target measurement in the period. Intensification was defined as any 1 of the following 3 occurrences: (1) an increase in the number of drug classes, (2) an increase in the daily dose of at least 1 ongoing drug class, or (3) a switch to a medication in a different drug class. A new insulin regimen was considered treatment intensification for hyperglycemia; titration of insulin dosages after insulin initiation could not be observed in the pharmacy database. Details on this method are available elsewhere.24
Systolic blood pressures and A1C and LDL-C levels obtained during 15 months after exiting from the program were compared between CM patients and their matched controls using hierarchical linear regression analysis adjusting for facility as a random effect and adjusting for baseline risk factor values as fixed effects. The latest available readings during the 15-month period were used as dependent variables in separate models for each CVD risk factor. In these models, CM versus control was the independent variable. Similar hierarchical logistic regression models were used to assess the effect of CM on good versus poor adherence to medication regimens for hyperglycemia, hyperlipidemia, and hypertension. Adherence to each regimen in the 12 months starting with the date of CM entry was modeled as a dependent variable, with CM versus control as the independent variable and with adjustments for medication adherence during the 12 months before CM entry as fixed effects. Hierarchical logistic regression analysis was used to model the probability of receiving treatment intensification for hyperglycemia, hyperlipidemia, and hypertension during the 12 months following CM entry, with CM versus control as the independent variable. All models adjusted for propensity score as a fixed effect and for facility as a random effect.
All analyses were performed using SAS version 9.1 (SAS Institute Inc, Cary, NC). This study was reviewed and approved by the institutional review board of Kaiser Permanente.
A total of 179,249 patients with diabetes met the criteria for inclusion in the study (Table). Eight percent of these patients entered the CM program in 2003. There were modest differences between CM patients and patients who did not enter CM in terms of age, sex, and LDL-C levels; SBP differences were not significantly different between the 2 groups. The greatest differences between patients entering CM and those who did not were related to program entry criteria, including the mean A1C level (9.0% and 7.0%, respectively), the prevalence of microalbuminuria (17% and 9%, respectively), and diabetes-related hospitalizations or ED visits (13% and 6%, respectively).
Among patients who entered CM, 84% (Table) met at least 1 of the specified entry criteria into the program. Thirtythree percent of patients who did not enter CM met at least 1 of the specified entry criteria. Patients who were in CM stayed in the program for a mean of 8 months.