Predictors of office-based diabetic quality of care

OBJECTIVE-- In 1994, the Oregon Health Plan (OHP) expanded basic Medicaid insurance to residents under the federal poverty limit, adopted a prioritized limited benefits package, and converted to managed care. The quality of care in predominantly Medicaid populations with diabetes has not been previously described. In OHP enrollees, we examined predictors of diabetes care based on American Diabetes Association guidelines and described OHP diabetes care compared with national benchmarks.

RESEARCH DESIGN AND METHODS-- Chart abstraction and Medicaid data for 1995-1996 yielded 996 nonpregnant diabetic patients who were 18-64 years of age. Using [HbA.sub.1c], lipid panel, and urine protein/microalbumin documentation ordered during the study year, we constructed a standard care (SC) index: SC for all three tests, mixed care (MC) for one to two tests, or no tests documented (NTD).

RESULTS-- Our sample was predominantly white, 48 [+ or -] 11 years of age, 63% women, with 8 [+ or -] 5 provider visits. Providers ordered [HbA.sub.1c] (70%), urine microalbumin/protein (57%), and lipid panel (41%) tests. Patients distributed into SC (22%), MC (62%), or NTD (16%). Thirteen variables predicted SC. Patients had a higher likelihood of SC if they were 18-24 years of age, had more clinic visits, were on insulin daily, were in several comorbid groups, were enrolled in salaried or capitated health plans, or lived in counties with more hospital beds. Four studies were used as comparable national benchmarks.

CONCLUSIONS-- Care provided to OHP patients with diabetes compares favorably with national benchmarks. Yet, most OHP patients with diabetes are still not achieving optimal care. Examining predictors of SC may play an important role in further policy development.

The quality of care provided to the 36 million Medicaid patients has come under increasing scrutiny as health care providers, governmental agencies, and consumers ask the critical question, "What kind of care are we providing for Medicaid's $230 billion?" [1-4]. As administrators of this federal/state insurance program, individual states, through a variety of methods, have sought to improve both medical care and access to care for their low-income residents while controlling rising costs [5,6]. In 1994, the State of Oregon sought to provide basic medical coverage to more than 275,000 Oregon residents with incomes below the federal poverty limit by enrolling them into managed care, expanding Medicaid eligibility, and increasing overall provider reimbursement [7,8]. The Oregon Health Plan (OHP) was criticized because of concerns that it would compromise patient care, because it explicitly rationed services through a prioritized diagnosis/treatment limited-benefits package [9,10]. Further, as Oregon shifted from providing to purchasing medical care [11], concerns about underutilization of medical services increased [5].

Under the OHP, provision of quality care is a complex process, encompassing all aspects of the individual patient's interaction with the health care system. Quality evaluation may be reflected through the health plan infrastructure and resource availability, patient access, patient interactions with provider/ancillary personnel, provider delivery of care, cost, or patient satisfaction, adherence, and clinical outcome [12-15]. Recently, practice guidelines from national societies and the advent of mandatory reporting measures have focused on one aspect of quality--delivery of service. Physician disease management is often assessed by evaluating the care of patients with diabetes, due to validated care standards that can reduce cost, morbidity, and mortality. The Health Care Financing Administration (HCFA), which funds Medicare, selected improvement in diabetes care as a national priority. Through the Diabetes Quality Improvement Project in 2000, HCFA will evaluate process of care measures, such as ordering an [HbA.sub.1c] test at least yearly using the Health Plan Employer Data and Information Set [16, 17]. Although medical care of individual patients must be tailored, patterns emerging through population-based evaluation provide insight into the process of care delivery [17]. These process benchmarks are only one of an array of quality indicators, but they provide context as measurable provider contributions to quality medical care.

We sought to evaluate one aspect of quality medical care for adult OHP enrollees, using diabetes as a tracer condition. The purpose of our study was threefold: 1) to determine predictors of standard care (SC) in the OHP in the office setting, 2) to compare the provision of different aspects of care, and 3) to benchmark the quality of OHP diabetes care against other published reports. Despite the increasing focus on the quality of care rendered in government-sponsored programs, the quality of diabetes care in predominantly Medicaid and low-income expansion populations has not been previously reported.

RESEARCH DESIGN AND METHODS

Model and data sources

To address our study goals, we used the Agency for Healthcare Research and Quality framework for using clinical guidelines in assessing health care quality [18]. This model describes commonly accepted relationships between input (e.g., demographic and clinical risk factors), process of care (e.g., diagnostic testing and procedures), and outcome variables (e.g., morbidity and health status). We examined the relationship between input and process, rather than outcome measures such as mortality or hospital admissions. The management of diabetes is rendered primarily on an outpatient basis; therefore, office-based quality of care was determined from chart review, using American Diabetes Association (ADA) standards [19]. Provider ordering of three laboratory tests was used to construct an SC index. We also examined correlations between other ADA benchmarks not evaluated in our index. Finally, comparison benchmarks were generated after literature review.

Four data sources from calendar year 1995 were examined: 1) chart data abstracted for clinical information; 2) Medicaid encounter data from participating managed care organizations [MCOs] or physician groups for International Classification of Diseases, Ninth Revision [ICD-9] and demographic information; 3) Area Resource File (ARE) [20] for patient county information; and 4) 1994 site visit data for MCO payment to individual physicians or physician groups.

To ensure reliability a random sample of patient charts was abstracted by three clinical supervisors (two registered nurses and one medical doctor) from Peer Review Systems of Oregon, and consensus was achieved after group review Using these "gold standard" chart abstractions, four nurses trained for 80 h over the course of 3 weeks, reaching 90% agreement on abstracted fields. Charts from the primary care physician, identified by the Oregon Office of Medical Assistance Programs, were abstracted in the physician's clinic using scannable records. Clinic staff clarified handwriting and ambiguous comments. Medicaid and chart data were merged though unique patient identifiers. County medical and socioeconomic characteristics were merged using the patient's county of residence. The OHP's management system was tiered, with payment capitated to most participating MCOs. However, payment to individual physicians or physician groups varied and was clarified during a 1994 site visit through interviews with health plan m anagers and physicians.

Patient sample

Inclusion criteria were based on ICD-9 coding in Medicaid encounter data and chart abstraction data. All OHP patients were included and sampled if they had at least one ICD-9-Clinical Modification diagnosis of diabetes [21-24] (250.xx), were OHP-enrolled for at least 10 of 12 months in 1995, and were 18 years of age or older during the study period from 1 February 1995 to 31 January 1996. There were 1,512 patients who were initially identified and who had chart abstractions performed for all primary care clinic visits during this study period. After chart abstraction, 298 additional patients did not meet inclusion criteria--there was no charted reference to diabetes (n = 175), or they were 65 years of age or older (n = 123), thus making them dually eligible for OHP and Medicare coverage.

Of the remaining 1,214 patients, 219 were excluded because of the following reasons: key dependent variables were missing (69.xx), charts were not produced (32.xx), they were pregnant (18.xx), Medicaid claims data were not available (10.xx), or other miscellaneous reasons (91.xx). No patients were on dialysis. Fourteen additional patients were excluded because of obvious data entry errors--863 office visits in a year, for example. Thus, our final data set comprised 996 patients (82%).

SC index