Sarang Deo

The Impact of Size and Occupancy of Hospital on the Extent of Ambulance Diversion: Theory and Evidence

In recent years, growth in the demand for emergency medical services, along with decline in the number of hospitals with emergency departments (EDs), has raised concerns about the ability of the EDs to provide adequate service. Many EDs frequently report periods of overcrowding during which they are forced to divert incoming ambulances to neighboring hospitals, a phenomenon known as “ambulance diversion.” The objective of this paper is to study the impact of key operational characteristics of the hospitals such as the number of ED beds, the number of inpatient beds, and the utilization of inpatient beds on the extent to which hospitals go on ambulance diversion. We propose a simple queueing network model to describe the patient flow between the ED and the inpatient department. We analyze this network using two different approximations—diffusion and fluid—to derive two separate sets of measures for inpatient occupancy and ED size. We use these sets of measures to form hypotheses and test them by estimating...

Rental price and rental duration under retail competition

Consider a retailer that rents products to customers for a pre-specified rental duration. By considering the dynamics of uncertain rental demand and return processes, we first present a base model that is intended to analyze the impact of rental duration on the stocking level, the rental price, and the retailer’s profit. Due to the complexity of the base model, we develop an approximation scheme to obtain tractable results. Also, we apply the base model to analyze a situation in which a retailer enters a revenue sharing agreement with a distributor. Moreover, we expand our base model to address the issue of competition in rental duration and rental price. The analysis of our competitive model in a duopolistic environment suggests that the market equilibrium depends on the market potential and the rental duration sensitivity. Furthermore, we establish conditions under which one firm will charge a lower rental price while the other firm will offer a longer rental duration in equilibrium.

Do Diagnosis Delays Impact Receipt of Test Results? Evidence from the HIV Early Infant Diagnosis Program in Uganda

Background There is scant evidence on the association between diagnosis delays and the receipt of test results in HIV Early Infant Diagnosis (EID) programs. We determine the association between diagnosis delays and other health care system and patient factors on result receipt. Methods We reviewed 703 infant HIV test records for tests performed between January 2008 and February 2009 at a regional referral hospital and level four health center in Uganda. The main outcome was caregiver receipt of the test result. The primary study variable was turnaround time (time between sample collection and result availability at the health facility). Additional variables included clinic entry point, infant age at sample collection, reported HIV status and receipt of antiretroviral prophylaxis for prevention of mother-to-child transmission. We conducted a pooled analysis in addition to separate analyses for each facility. We estimated the relative risk of result receipt using modified Poisson regression with robust standard errors. Results Overall, the median result turnaround time, was 38 days. 59% of caregivers received infant test results. Caregivers were less likely to receive results at turnaround times greater than 49 days compared to 28 days or fewer (ARR = 0.83; 95% CI = 0.70–0.98). Caregivers were more likely to receive results at the PMTCT clinic (ARR = 1.81; 95% CI = 1.40–2.33) and less likely at the pediatric ward (ARR = 0.54; 95% CI = 0.37–0.81) compared to the immunization clinic. At the level four health center, result receipt was half as likely among infants older than 9 months compared to 3 months and younger (ARR= 0.47; 95% CI = 0.25–0.93). Conclusion In this study setting, we find evidence that longer turnaround times, clinic entry point and age at sample collection may be associated with receipt of infant HIV test results.

Improving Health Outcomes Through Better Capacity Allocation in a Community-Based Chronic Care Model

This paper studies a model of community-based healthcare delivery for a chronic disease. In this setting, patients periodically visit the healthcare delivery system, which influences their disease progression and consequently their health outcomes.

Modeling the Impact of Integrating HIV and Outpatient Health Services on Patient Waiting Times in an Urban Health Clinic in Zambia

Background Rapid scale up of HIV treatment programs in sub-Saharan Africa has refueled the long-standing health policy debate regarding the merits and drawbacks of vertical and integrated system. Recent pilots of integrating outpatient and HIV services have shown an improvement in some patient outcomes but deterioration in waiting times, which can lead to worse health outcomes in the long run. Methods A pilot intervention involving integration of outpatient and HIV services in an urban primary care facility in Lusaka, Zambia was studied. Data on waiting time of patients during two seven-day periods before and six months after the integration were collected using a time and motion study. Statistical tests were conducted to investigate whether the two observation periods differed in operational details such as staffing, patient arrival rates, mix of patients etc. A discrete event simulation model was constructed to facilitate a fair comparison of waiting times before and after integration. The simulation model was also used to develop alternative configurations of integration and to estimate the resulting waiting times. Results Comparison of raw data showed that waiting times increased by 32% and 36% after integration for OPD and ART patients respectively (p<0.01). Using simulation modeling, we found that a large portion of this increase could be explained by changes in operational conditions before and after integration such as reduced staff availability (p<0.01) and longer breaks between consecutive patients (p<0.05). Controlling for these differences, integration of services, per se, would have resulted in a significant decrease in waiting times for OPD and a moderate decrease for HIV services. Conclusions Integrating health services has the potential of reducing waiting times due to more efficient use of resources. However, one needs to ensure that other operational factors such as staff availability are not adversely affected due to integration.

Associations between organizational characteristics and quality improvement activities of clinics participating in a quality improvement collaborative.

Background:Few studies have rigorously evaluated the associations between organizational characteristics and intervention activities of health care organizations participating in quality improvement collaboratives (QICs). Objective:To examine the relationship between clinic characteristics and intervention activities by primary care clinics that provide HIV care and that participated in a QIC. Design:Cross-sectional study of Ryan White CARE Act (now called Ryan White HIV/AIDS Treatment Modernization Act) funded clinics that participated in a QIC over 16 months in 2000 and 2001. The QIC was originally planned to be a more typical 12 months long, but was extended to increase the likelihood of success. Data were collected using surveys of clinicians and administrators in participating clinics and monthly reports of clinic improvement activities. Measures:Number of interventions attempted, percent of interventions repeated, percent of interventions evaluated, and organizational characteristics. Results:Clinics varied significantly in their intervention choices. Organizations with a more open culture and a greater emphasis on quality improvement attempted more interventions (P < 0.01, P < 0.05) and interventions that were more comprehensive (P < 0.01, P < 0.10). Presence of multidisciplinary teams and measurement of progress toward quantifiable goals also were associated with comprehensiveness of interventions (P < 0.01, P < 0.05). Conclusion:Clinic characteristics predicted intervention activities during a QIC. Further research is needed on how these organizational characteristics affect quality of care through their influence on intervention activities.

Implementation and Operational Research: Expedited Results Delivery Systems Using GPRS Technology Significantly Reduce Early Infant Diagnosis Test Turnaround Times.

Abstract:The objective of this study was to quantify the impact of a new technology to communicate the results of an infant HIV diagnostic test on test turnaround time and to quantify the association between late delivery of test results and patient loss to follow-up. We used data collected during a pilot implementation of Global Package Radio Service (GPRS) printers for communicating results in the early infant diagnosis program in Mozambique from 2008 through 2010. Our dataset comprised 1757 patient records, of which 767 were from before implementation and 990 from after implementation of expedited results delivery system. We used multivariate logistic regression model to determine the association between late result delivery (more than 30 days between sample collection and result delivery to the health facility) and the probability of result collection by the infants caregiver. We used a sample selection model to determine the association between late result delivery to the facility and further delay in collection of results by the caregiver. The mean test turnaround time reduced from 68.13 to 41.05 days post–expedited results delivery system. Caregivers collected only 665 (37.8%) of the 1757 results. After controlling for confounders, the late delivery of results was associated with a reduction of approximately 18% (0.44 vs. 0.36; P < 0.01) in the probability of results collected by the caregivers (odds ratio = 0.67, P < 0.05). Late delivery of results was also associated with a further average increase in 20.91 days of delay in collection of results (P < 0.01). Early infant diagnosis program managers should further evaluate the cost-effectiveness of operational interventions (eg, GPRS printers) that reduce delays.

Planning for HIV Screening, Testing, and Care at the Veterans Health Administration

We analyzed the planning problem for HIV screening, testing, and care. This problem consists of determining the optimal fraction of patients to be screened in every period as well as the optimum staffing level at each part of the healthcare system to maximize the total health benefits to the patients measured by quality-adjusted life-years QALYs gained. We modeled this problem as a nonlinear mixed integer programming program comprising disease progression the transition of the patients across health states, system dynamics the flow of patients in different health states across various parts of the healthcare delivery system, and budgetary and capacity constraints. We applied the model to the Greater Los Angeles GLA station in the Veterans Health Administration system. We found that a Centers for Disease Control and Prevention recommended routine screening policy in which all patients visiting the system are screened for HIV irrespective of risk factors may not be feasible because of budgetary constraints. Consequently, we used the model to develop and evaluate managerially relevant policies within existent capacity and budgetary constraints to improve upon the current risk based screening policy of screening only high risk patients. Our computational analysis showed that the GLA station can achieve substantial increase 20% to 300% in the QALYs gained by using these policies over risk based screening. The GLA station has already adapted two of these policies that could yield better patient health outcomes over the next few years. In addition, our model insights have influenced the decision making process at this station.

Slow First, Fast Later: Empirical Evidence of Speed-up in Service Episodes of Finite Duration

There is increasing evidence that workers in many service settings regulate their work speed in response to operating conditions. However, in service episodes of finite duration characterized by time-varying and non-stationary dynamics (e.g., outpatient departments), operating variables that can affect work speed have not been rigorously studied. Understanding the impact of these drivers on work speed can help managers improve resource and appointment scheduling. We employ the trade-off faced by workers between cost of providing service and cost of customer wait in such environments to identify two previously unexplored drivers of work speed - time within the episode and anticipated remaining workload. We empirically test our predictions using data from a high volume, tertiary care outpatient department. We find that workers start a typical service episode at slower work speed and progressively speed-up toward the end of the service episode. As a result, incoming patients experience 23% shorter (50 minutes smaller) average length of stay at the middle, and 60% shorter (130 minutes smaller) toward the end of the service episode. Further, consistent with our conceptual framework, we find that the temporal pattern of speed-up is influenced by the anticipated workload during the service episode. Specifically, a higher anticipated workload leads to a larger increase in work speed earlier in the service episode than later. An increase in anticipated workload by 1 patient per hour leads to 9% (20 minutes) reduction in average length of stay at the beginning, only 4% (8 minutes) reduction during the middle and negligible change toward the end of the service episode. We also identify the role of reduction in discretionary task (ordering diagnostic tests) as one mechanism of achieving this speed-up, which itself is influenced by time within the service episode and anticipated remaining workload. These findings provide managers with several levers to improve efficiency and quality of service provision, e.g. overall shorter service episodes, increasing the staffing level earlier in the service episode and decreasing it later, and scheduling simpler patients earlier in the service episode.

Impact of organizational factors on adherence to laboratory testing protocols in adult HIV care in Lusaka, Zambia

BackgroundPrevious operational research studies have demonstrated the feasibility of large-scale public sector ART programs in resource-limited settings. However, organizational and structural determinants of quality of care have not been studied.MethodsWe estimate multivariate regression models using data from 13 urban HIV treatment facilities in Zambia to assess the impact of structural determinants on health workers’ adherence to national guidelines for conducting laboratory tests such as CD4, hemoglobin and liver function and WHO staging during initial and follow-up visits as part of Zambian HIV care and treatment program.ResultsCD4 tests were more routinely ordered during initial history and physical (IHP) than follow-up (FUP) visits (93.0 % vs. 85.5 %; p < 0.01). More physical space, higher staff turnover and greater facility experience with ART was associated with greater odds of conducting tests. Higher staff experience decreased the odds of conducting CD4 tests in FUP (OR 0.93; p < 0.05) and WHO staging in IHP visit (OR 0.90; p < 0.05) but increased the odds of conducting hemoglobin test in IHP visit (OR 1.05; p < 0.05). Higher staff burnout increased the odds of conducting CD4 test during FUP (OR 1.14; p < 0.05) but decreased the odds of conducting hemoglobin test in IHP visit (0.77; p < 0.05) and CD4 test in IHP visit (OR 0.78; p < 0.05).ConclusionPhysical space plays an important role in ensuring high quality care in resource-limited setting. In the context of protocolized care, new staff members are likely to be more diligent in following the protocol verbatim rather than relying on memory and experience thereby improving adherence. Future studies should use prospective data to confirm the findings reported here.