Coordination of Care as Experienced by the Specialist: Validation of the CSC-Specialist Survey in the Private Sector and the Effect of a Shared Electronic Health Record.

BACKGROUND: We previously developed 2 complementary surveys to measure coordination of care as experienced by the specialist and the primary care provider (PCP). These Coordination of Specialty Care (CSC) surveys were developed in the Veterans Health Administration (VA), under an integrated organizational umbrella that includes a shared electronic health record (EHR). OBJECTIVE: To develop an augmented version of the CSC-Specialist in the private sector and use that version (CSC-Specialist 2.0) to examine the effect of a shared EHR on coordination. RESEARCH DESIGN: We administered the survey online to a national sample of clinicians from 10 internal medicine subspecialties. We used multitrait analysis and confirmatory factor analysis to evaluate the psychometric properties of the original VA-based survey and develop an augmented private sector survey (CSC-Specialist 2.0). We tested construct validity by regressing a single-item measure of overall coordination onto the 4 scales. We used analysis of variance to examine the relationship of a shared EHR to coordination. RESULTS: Psychometric assessment supported the 13-item, 4-scale structure of the original VA measure and the augmented 18-item, 4-scale structure of the CSC-Specialist 2.0. The CSC-Specialist 2.0 scales together explained 45% of the variance in overall coordination. A shared EHR was associated with significantly better scores for the Roles and Responsibilities and Data Transfer scales, and for overall coordination. CONCLUSIONS: The CSC-Specialist 2.0 is a unique survey that demonstrates adequate psychometric performance and is sensitive to use of a shared EHR. It can be used alone or with the CSC-PCP to identify coordination problems, guide interventions, and measure improvements.

A two-state comparative implementation of peer-support intervention to link veterans to health-related services after incarceration: a study protocol.

BACKGROUND: Approximately 600,000 persons are released from prison annually in the United States. Relatively few receive sufficient re-entry services and are at risk for unemployment, homelessness, poverty, substance abuse relapse and recidivism. Persons leaving prison who have a mental illness and/or a substance use disorder are particularly challenged. This project aims to create a peer mentor program to extend the reach and effectiveness of reentry services provided by the Department of Veterans' Affairs (VA). We will implement a peer support for reentry veterans sequentially in two states. Our outcome measures are 1) fidelity of the intervention, 2) linkage to VA health care and, 3) continued engagement in health care. The aims for this project are as follows: (1) Conduct contextual analysis to identify VA and community reentry resources, and describe how reentry veterans use them. (2) Implement peer-support, in one state, to link reentry veterans to Veterans' Health Administration (VHA) primary care, mental health, and SUD services. (3) Port the peer-support intervention to another, geographically, and contextually different state. DESIGN: This intervention involves a 2-state sequential implementation study (Massachusetts, followed by Pennsylvania) using a Facilitation Implementation strategy. We will conduct formative and summative analyses, including assessment of fidelity, and a matched comparison group to evaluate the intervention's outcomes of veteran linkage and engagement in VHA health care (using health care utilization measures). The study proceeds in 3 phases. DISCUSSION: We anticipate that a peer support program will be effective at improving the reentry process for veterans, particularly in linking them to health, mental health, and SUD services and helping them to stay engaged in those services. It will fill a gap by providing veterans with access to a trusted individual, who understands their experience as a veteran and who has experienced justice involvement. The outputs from this project, including training materials, peer guidebooks, and implementation strategies can be adapted by other states and regions that wish to enhance services for veterans (or other populations) leaving incarceration. A larger cluster-randomized implementation-effectiveness study is planned. TRIAL REGISTRATION: This protocol is registered with clinicaltrials.gov on November 4, 2016 and was assigned the number NCT02964897 .

Electronic consultations (e-consults) to improve access to specialty care: a systematic review and narrative synthesis.

BACKGROUND: We define electronic consultations ("e-consults") as asynchronous, consultative, provider-to-provider communications within a shared electronic health record (EHR) or web-based platform. E-consults are intended to improve access to specialty expertise for patients and providers without the need for a face-to-face visit. Our goal was to systematically review and summarize the literature describing the use and effects of e-consults. METHODS: We searched PubMed, EMBASE, the Cochrane Library, and CINAHL for studies related to e-consults published between 1990 through December 2014. Three reviewers identified empirical studies and system descriptions, including articles on systems that used a shared EHR or web-based platform, connected providers in the same health system, were used for two-way provider communication, and were text-based. RESULTS: Our final review included 27 articles. Twenty-two were research studies and five were system descriptions. Eighteen originated from one of three sites with well-developed e-consult programs. Most studies reported on workflow impact, timeliness of specialty input, and/or provider perceptions of e-consults. E-consultations are used in a variety of ways within and across medical centers. They provide timely access to specialty care and are well-received by primary care providers. DISCUSSION: E-consults are feasible in a variety of settings, flexible in their application, and facilitate timely specialty advice. More extensive and rigorous studies are needed to inform the e-consult process and describe its effect on access to specialty visits, cost and clinical outcomes.

Resource use and guideline concordance in evaluation of pulmonary nodules for cancer: too much and too little care.

IMPORTANCE: Pulmonary nodules are common, and more will be found with implementation of lung cancer screening. How potentially malignant pulmonary nodules are evaluated may affect patient outcomes, health care costs, and effectiveness of lung cancer screening programs. Guidelines for evaluating pulmonary nodules for cancer exist, but little is known about how nodules are evaluated in the usual care setting. OBJECTIVE: To characterize nodule evaluation and concordance with guidelines. DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort study was conducted including detailed review of medical records from pulmonary nodule detection through evaluation completion, cancer diagnosis, or study end (December 31, 2012). The participants included 300 adults with pulmonary nodules from 15 Veterans Affairs hospitals. MAIN OUTCOMES AND MEASURES: Resources used for evaluation at any Veterans Affairs facility and guideline-concordant evaluation served as the main outcomes. RESULTS: Twenty-seven of 300 patients (9.0%) with pulmonary nodules ultimately received a diagnosis of lung cancer: 1 of 57 (1.8%) with a nodule of 4 mm or less, 4 of 134 (3.0%) with a nodule of 5 to 8 mm, and 22 of 109 (20.2%) with a nodule larger than 8 mm. Nodule evaluation entailed 1044 imaging studies, 147 consultations, 76 biopsies, 13 resections, and 21 hospitalizations. Radiographic surveillance (n = 277) lasted a median of 13 months but ranged from less than 0.5 months to 8.5 years. Forty-six patients underwent invasive procedures (range per patient, 1-4): 41.3% (19 patients) did not have cancer and 17.4% (8) experienced complications, including 1 death. Notably, 15 of the 300 (5.0%) received no purposeful evaluation and had no obvious reason for deferral, seemingly "falling through the cracks." Among 197 patients with a nodule detected after release of the Fleischner Society guidelines, 44.7% received care inconsistent with guidelines (17.8% overevaluation, 26.9% underevaluation). In multivariable analyses, the strongest predictor of guideline-inconsistent care was inappropriate radiologist recommendations (overevaluation relative risk, 4.6 [95% CI, 2.3-9.2]; underevaluation, 4.3 [2.7-6.8]). Other systems factors associated with underevaluation included receiving care at more than 1 facility (2.0 [1.5-2.7]) and nodule detection during an inpatient or preoperative visit (1.6 [1.1-2.5]). CONCLUSIONS AND RELEVANCE: Pulmonary nodule evaluation is often inconsistent with guidelines, including cases with no workup and others with prolonged surveillance or unneeded procedures that may cause harm. Systems to improve quality (eg, aligning radiologist recommendations with guidelines and facilitating communication across providers) are needed before lung cancer screening is widely implemented.

Guideline-recommended medications: variation across Medicare Advantage plans and associated mortality.

OBJECTIVES: To evaluate variation in the prescription of guideline-recommended medications across Medicare Advantage (MA) plans and to determine whether such variation is associated with increased mortality. METHODS: Observational study of 111,667 patients aged 65 years or older receiving care in 203 MA plans. We linked data from the Medicare Health Outcomes (HOS) Survey cohort 9 (April 2006-May 2008) with the Medicare Part D prescription benefit files (January 1, 2006-December 31, 2007) to examine variation in treatment across MA plans and its association with differences in observed (O)/expected (E) mortality ratio for 5 high-volume chronic conditions: diabetes, coronary artery disease (CAD), congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD)/asthma, and depression. RESULTS: Analysis of variance confirmed that the 203 MA plans differed significantly in their use of guideline-recommended treatment (P≤0.02). Those MA plans with higher use of angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (r=-0.40; P<0.0001) and beta-blockers (r=-0.27; P<0.0001) in patients with CHF were significantly associated with lower O/E mortality ratios. Those MA plans with higher use of multiple guideline-recommended medications were significantly associated with lower O/E mortality ratios in CHF (r=-0.45; P<0.0001) and diabetes (r=-0.14; P<0.042). There were no significant associations between the variation in performance indicators and mortality ratios in patients with CAD and COPD/asthma. Those MA plans with higher use of antidepressant medications had significantly higher O/E mortality ratios (r=0.28, P<0.0001). CONCLUSIONS: There was wide variation across MA plans in the prescription of guideline-recommended medications that had a measurable relationship to the mortality of elderly patients with CHF and diabetes. These findings can serve to both motivate and target quality improvement programs.

Going beyond patient classification systems to create an evidence-based staffing methodology.

The Department of Veterans Affairs developed a nationally standardized nurse staffing methodology, using an evidence-based process. We present an overview, linking an integrative review of recent literature on patient classification systems, interdisciplinary expert panel consultation, operational feasibility assessment, and frontline manager involvement. This resulted in 7 candidate indicators for inclusion in unit-specific staffing models. Adaptable to all healthcare settings, this process goes beyond traditional patient classification systems.

A classification of diabetic foot infections using ICD-9-CM codes: application to a large computerized medical database.

BACKGROUND: Diabetic foot infections are common, serious, and varied. Diagnostic and treatment strategies are correspondingly diverse. It is unclear how patients are managed in actual practice and how outcomes might be improved. Clarification will require study of large numbers of patients, such as are available in medical databases. We have developed and evaluated a system for identifying and classifying diabetic foot infections that can be used for this purpose. METHODS: We used the (VA) Diabetes Epidemiology Cohorts (DEpiC) database to conduct a retrospective observational study of patients with diabetic foot infections. DEpiC contains computerized VA and Medicare patient-level data for patients with diabetes since 1998. We determined which ICD-9-CM codes served to identify patients with different types of diabetic foot infections and ranked them in declining order of severity: Gangrene, Osteomyelitis, Ulcer, Foot cellulitis/abscess, Toe cellulitis/abscess, Paronychia. We evaluated our classification by examining its relationship to patient characteristics, diagnostic procedures, treatments given, and medical outcomes. RESULTS: There were 61,007 patients with foot infections, of which 42,063 were classifiable into one of our predefined groups. The different types of infection were related to expected patient characteristics, diagnostic procedures, treatments, and outcomes. Our severity ranking showed a monotonic relationship to hospital length of stay, amputation rate, transition to long-term care, and mortality. CONCLUSIONS: We have developed a classification system for patients with diabetic foot infections that is expressly designed for use with large, computerized, ICD-9-CM coded administrative medical databases. It provides a framework that can be used to conduct observational studies of large numbers of patients in order to examine treatment variation and patient outcomes, including the effect of new management strategies, implementation of practice guidelines, and quality improvement initiatives.

Variation in antibiotic treatment for diabetic patients with serious foot infections: a retrospective observational study.

BACKGROUND: Diabetic foot infections are common, serious, and diverse. There is uncertainty about optimal antibiotic treatment, and probably substantial variation in practice. Our aim was to document whether this is the case: A finding that would raise questions about the comparative cost-effectiveness of different regimens and also open the possibility of examining costs and outcomes to determine which should be preferred. METHODS: We used the Veterans Health Administration (VA) Diabetes Epidemiology Cohorts (DEpiC) database to conduct a retrospective observational study of hospitalized patients with diabetic foot infections. DEpiC contains computerized VA and Medicare patient-level data for VA patients with diabetes since 1998, including demographics, ICD-9-CM diagnostic codes, antibiotics prescribed, and VA facility. We identified all patients with ICD-9-CM codes for cellulitis/abscess of the foot and then sub-grouped them according to whether they had cellulitis/abscess plus codes for gangrene, osteomyelitis, skin ulcer, or none of these. For each facility, we determined: 1) The proportion of patients treated with an antibiotic and the initial route of administration; 2) The first antibiotic regimen prescribed for each patient, defined as treatment with the same antibiotic, or combination of antibiotics, for at least 5 continuous days; and 3) The antibacterial spectrum of the first regimen. RESULTS: We identified 3,792 patients with cellulitis/abscess of the foot either alone (16.4%), or with ulcer (32.6%), osteomyelitis (19.0%) or gangrene (32.0%). Antibiotics were prescribed for 98.9%. At least 5 continuous days of treatment with an unchanged regimen of one or more antibiotics was prescribed for 59.3%. The means and (ranges) across facilities of the three most common regimens were: 16.4%, (22.8%); 15.7%, (36.1%); and 10.8%, (50.5%). The range of variation across facilities proved substantially greater than that across the different categories of foot infection. We found similar variation in the spectrum of the antibiotic regimen. CONCLUSIONS: The large variations in regimen appear to reflect differences in facility practice styles rather than case mix. It is unlikely that all regimens are equally cost-effective. Our methods make possible evaluation of many regimens across many facilities, and can be applied in further studies to determine which antibiotic regimens should be preferred.

Comparison of health outcomes for male seniors in the Veterans Health Administration and Medicare Advantage plans.

OBJECTIVES: To compare the Veterans Health Administration (VHA) with the Medicare Advantage (MA) plans with regard to health outcomes. DATA SOURCES: The Medicare Health Outcome Survey, the 1999 Large Health Survey of Veteran Enrollees, and the Ambulatory Care Survey of Healthcare Experiences of Patients (Fiscal Years 2002 and 2003). STUDY DESIGN: A retrospective study. EXTRACTION METHODS: Men 65+ receiving care in MA (N=198,421) or in VHA (N=360,316). We compared the risk-adjusted probability of being alive with the same or better physical (PCS) and mental (MCS) health at 2-years follow-up. We computed hazard ratio (HR) for 2-year mortality. PRINCIPAL FINDINGS: Veterans had a higher adjusted probability of being alive with the same or better PCS compared with MA participants (VHA 69.2 versus MA 63.6 percent, p<.001). VHA patients had a higher adjusted probability than MA patients of being alive with the same or better MCS (76.1 versus 69.6 percent, p<.001). The HRs for mortality in the MA were higher than in the VHA (HR, 1.26 [95 percent CI 1.23-1.29]). CONCLUSIONS: Our findings indicate that the VHA has better patient outcomes than the private managed care plans in Medicare. The VHA's performance offers encouragement that the public sector can both finance and provide exemplary health care.

Differences in risk-adjusted mortality between medicaid-eligible patients enrolled in medicare advantage plans and those enrolled in the veterans health administration.

BACKGROUND: We compared risk-adjusted mortality rates between Medicaid-eligible patients in the Medicare Advantage plans ("MA dual enrollees") and Medicaid-eligible patients in the Veterans Health Administration ("VHA dual enrollees"). METHODS: We used the Death Master File to ascertain the vital status of 1912 MA and 2361 VHA dual enrollees. We used Cox regression models to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: The 3-year mortality rates of VHA and MA dual enrollees were 15.8% and 19.0%, respectively. The adjusted HR of mortality in the MA dual enrollees was significantly higher than in the VHA dual enrollees (HR, 1.260 [95% CI, 1.044-1.520]). This was also the case for elderly patients and those from racial/ethnic minority groups. CONCLUSIONS: The VHA had better health outcomes than did MA plans. The VHA's performance is reassuring, given its emphasis on equal access to healthcare in an environment that is less dependent on patient financial considerations.

Updated U.S. population standard for the Veterans RAND 12-item Health Survey (VR-12).

PURPOSE: The purpose of this project was to develop an updated U.S. population standard for the Veterans RAND 12-item Health Survey (VR-12). METHODS: We used a well-defined and nationally representative sample of the U.S. population from 52,425 responses to the Medical Expenditure Panel Survey (MEPS) collected between 2000 and 2002. We applied modified regression estimates to update the non-proprietary 1990 scoring algorithms. We applied the updated standard to the Medicare Health Outcomes Survey (HOS) to compute the VR-12 physical (PCS((MEPS standard))) and mental (MCS((MEPS standard))) component summaries based on the MEPS. We compared these scores to PCS and MCS based on the 1990 U.S. population standard. RESULTS: Using the updated U.S. population standard, the average VR-12 PCS((MEPS standard)) and MCS((MEPS standard)) scores in the Medicare HOS were 39.82 (standard deviation [SD] = 12.2) and 50.08 (SD = 11.4), respectively. For the same Medicare HOS, the average PCS and MCS scores based on the 1990 standard were 1.40 points higher and 0.99 points lower in comparison to VR-12 PCS and MCS, respectively. CONCLUSIONS: Changes in the U.S. population between 1990 and today make the old standard obsolete for the VR-12, so the updated standard developed here is widely available to serve as such a contemporary standard for future applications for health-related quality of life (HRQoL) assessments.

Angioedema incidence in US veterans initiating angiotensin-converting enzyme inhibitors.

Angioedema is a rare but potentially serious complication of angiotensin-converting enzyme inhibitor (ACE) use. We conducted a study to estimate incidence of ACE-related angioedema and explore its determinants in a large racially diverse patient population. We used linked medical and pharmacy records to identify all patients in the US Veterans Affairs Health Care System from April 1999 through December 2000 who received first prescriptions for antihypertensive medications. We studied 195 192 ACE initiators and 399 889 patients initiating other antihypertensive medications (OAH). New angioedema was identified by diagnosis codes using methods validated in a national sample of 869 angioedema cases with confirmation for over 95% of cases. Overall, 0.20% of ACE initiators developed angioedema while on the medication and the incidence rate was 1.97 (1.77 to 2.18) cases per 1000 person years. This compares with a rate of 0.51 (0.43 to 0.59) in OAH initiators and the adjusted relative risk estimate was 3.56 (2.82 to 4.44). Fifty five percent of cases occurred within 90 days of first ACE use but risk remained elevated with prolonged use, even beyond 1 year. We estimate that 58.3% of angioedema in patients starting antihypertensives was related to ACE. We also found that angioedema rates were nearly 4-fold higher in blacks, 50% higher in women, and 12% lower in those with diabetes. This study provides a reliable estimate of angioedema incidence associated with ACE use in a diverse nontrial patient population, confirming that the incidence is low, but finding substantial variation by race, sex, and diabetes status.

Potentially inappropriate prescribing for the elderly: effects of geriatric care at the patient and health care system level.

BACKGROUND: Many studies have identified patient characteristics associated with potentially inappropriate prescribing in the elderly (PIPE), however, little attention has been directed toward how health care system factors such as geriatric care may affect this patient safety issue. OBJECTIVE: This study examines the association between geriatric care and PIPE in a community dwelling elderly population. RESEARCH DESIGN: Cross-sectional retrospective database study. SUBJECTS: Veterans age > or =65 years who received health care in the VA system during Fiscal Years (FY99-00), and also received at medications from the Veterans Administration in FY00. MEASURES: PIPE was identified using the Zhan adaptation of the Beers criteria. Geriatric care penetration was calculated as the proportion of patients within a facility who received at least 1 geriatric outpatient clinic or inpatient visit. ANALYSES: Logistic regression models with generalized estimating equations were used to assess the relationship between geriatric care and PIPE after controlling for patient and health care system characteristics. RESULTS: Patients receiving geriatric care were less likely to have PIPE exposure (odds ratio, 0.64; 95% confidence interval, 0.59-0.73). There was also a weak effect for geriatric care penetration, with a trend for patients in low geriatric care penetration facilities having higher risk for PIPE regardless of individual geriatric care exposure (odds ratio, 1.14; 95% confidence interval, 0.99-1.30). CONCLUSIONS: Although geriatric care is associated with a lower risk of PIPE, additional research is needed to determine if heterogeneity in the organization and delivery of geriatric care resulted in the weak effect of geriatric care penetration, or whether this is a result of low power.

Health care resource utilization and expenditures associated with the use of insulin glargine.

BACKGROUND: Newer insulins, such as long-acting analogues, offer promise of better glycemic control, reduced risk for diabetes complications, and moderation of health care use and costs. OBJECTIVE: We studied initiation of insulin glargine to evaluate its association with subsequent health service utilization and estimated expenditures. METHODS: Patients of the Veterans Health Administration, US Department of Veterans Affairs (VA) who initiated insulin glargine (n=5064) in 2001-2002 were compared with patients receiving other insulin (n=69,944), matched on prescription month (index date). Inpatient and outpatient VA care in the 12 months after a patient's index date was evaluated using Tobit regression, controlling for prior utilization, demographic characteristics, comorbidities, glycosylated hemoglobin (HbA(1c)) levels, and diabetes severity. National average utilization costs and medication acquisition costs were used to estimate the value of VA expenditures. RESULTS: Compared with other insulin users, insulin glargine initiators had higher HbA(1c) values (8.72% vs 8.16%) prior to the index date, but greater subsequent HbA(1c) reduction (-0.50% vs -0.22%). After adjustment for age, prior utilization, HbA(1c) levels, and other factors, insulin glargine initiation was associated with 2.4 (95% CI, 1.1-3.7) fewer inpatient days for patients with any hospital admission (US $820 lower costs per initiator), 1.6 (1.2-1.9) more outpatient encounters ($279 higher costs per initiator), and $374 ($362-$387) higher costs for diabetes medications. The net difference was an average lower VA cost of $166 (-$290 to $622) per patient. CONCLUSIONS: Insulin glargine use was associated with decreased inpatient days but increased outpatient care, and the value of the net change in utilization to VA offset the additional medication expenditures. Initiation of insulin glargine improves glycemic control and may reduce time in hospital without additional use of health resources.

Change in health status and mortality as indicators of outcomes: comparison between the Medicare Advantage Program and the Veterans Health Administration.

BACKGROUND: Comparing health outcomes with adequate methodology is central to performance assessments of health care systems. We compared the Medicare Advantage Program (MAP) and the Veterans Health Administration (VHA) with regard to changes in health status and mortality. METHODS: We used the Death-Master-File for vital status and the Short-Form 36 to determine physical (PCS) and mental (MCS) health at baseline and at 2 years. We compared the probability of being alive with the same or better (than would be expected by chance) PCS (or MCS) at 2 years and mortality, while adjusting for case-mix. Given the geographic variations in MAP enrollment, we did a regional sub-analysis. RESULTS: There were no significant differences in the probability of being alive with the same or better PCS except for the South (VHA 65.8% vs. MAP 62.5%, P = .0014). VHA patients had a slightly higher probability than MAP patients of being alive with the same or better MCS (71.8% vs. 70.1%, P = .002) but no significant regional variations. The hazard ratios for mortality in the MAP were higher than in the VHA across all regions. CONCLUSION: With the use of appropriate methodology, we found small differences in 2-year health outcomes that favor the VHA.

Risk-adjusted mortality as an indicator of outcomes: comparison of the Medicare Advantage Program with the Veterans' Health Administration.

BACKGROUND: The Medicare Advantage Program (MAP) and the Veterans' Health Administration (VHA) currently provide many services that benefit the elderly, and a comparative study of their risk-adjusted mortality rates has the potential to provide important information regarding these 2 systems of care. OBJECTIVE: The objective of this retrospective study was to compare mortality rates between the MAP and the VHA after controlling for case-mix differences. SUBJECTS: This study consisted of 584,294 MAP patients and 420,514 VHA patients. MEASURES: We used the Death Master File to ascertain the vital status of each study subject over approximately 4 years. We used Cox regression models to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for the MAP compared with VHA patients. RESULTS: The average age for male MAP patients was 73.8 years (+/- 5.6) and for male VHA patients was 74.05 years (+/- 6.3). Unadjusted mortality rates of males for VHA and MAP were 25.7% and 22.8%, respectively, over approximately 4 years (P < 0.0001), respectively. The case-mix of VHA patients, however, was sicker than those from MAP. After adjusting for case-mix, the HR for mortality in the MAP was significantly higher than that in the VHA (HR, 1.404; 95% CI = 1.383-1.426). We obtained similar results when we compared the mortality rates of females for VHA and MAP. CONCLUSIONS: After adjusting for their higher prevalence of chronic disease and worse self-reported health, mortality rates were lower for patients cared for in the VHA compared with those in the MAP. Further studies should examine what differences in care structures and processes contribute to lower mortality in the VHA.

Three complementary definitions of polypharmacy: methods, application and comparison of findings in a large prescription database.

PURPOSE: To develop and compare three operational definitions of polypharmacy using a large prescription database. METHODS: We defined Cumulative polypharmacy as all prescriptions filled during a 178 day window--which captured 95% of eventual refills as calculated from Kaplan-Meier and cumulative incidence curves. Continuous polypharmacy was all prescriptions filled in two such windows 6 months apart. Simultaneous polypharmacy was the number of prescriptions active on a particular day, as determined by fill dates and amount of medication given. We applied these definitions to the outpatient prescription files of New England veterans and compared the resulting estimates of polypharmacy using descriptive statistics. RESULTS: 118,013 patients received at least one prescription between January 1998 and July 1999. Cumulative polypharmacy averaged 3.54 (SD = 4.95) medications and continuous polypharmacy averaged 1.96 (SD = 3.23). Examination of simultaneous polypharmacy over 40 2-week intervals revealed an average of 2.63 (CI 2.61-2.65), a minimum of 1.09 (CI 1.08-1.10) and maximum of 4.94 (CI 4.92-4.96). One arbitrarily selected observation point had an average of 3.87 (SD = 3.17). CONCLUSIONS: Our definitions of cumulative and continuous polypharmacy serve to set upper and lower bounds for the estimate of polypharmacy. Our method for simultaneous polypharmacy gives numbers that diverge in some respects, but it is better at showing transient changes in medications. The methods are complementary and allow exploration of various aspects of medication use, such as cumulative medication exposure over time, the influence of chronic medical problems, and the causes of rapid changes in medications.