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Survival Analysis of Patients Undergoing Mechanical Ventilation with Tracheostomy in New York State 1992-1996: Does Managed Care Influence Outcome for DRG 483? . Diane M. Dewar, PhD University at Albany, State University of New York Jean-Paul Hafner, MD, MPH Stratton VA Medical Center and
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Survival Analysis of Patients Undergoing Mechanical Ventilation with Tracheostomy in New York State 1992-1996: Does Managed Care Influence Outcome for DRG 483? Diane M. Dewar, PhD University at Albany, State University of New York Jean-Paul Hafner, MD, MPH Stratton VA Medical Center and University at Albany, State University of New York
Critical Care Services’ Impact on Health Care Expenditures • Critical care has a significant impact on health care expenditures in the United States • 1-1.5% of gross domestic product • 7-8% of total health care expenditures nationwide • 20-34% of all hospital expenditures • 50% of critical care expenditures are allocated to patients with prolonged mechanical ventilation • only 10% of critical care unit patients have prolonged mechanical ventilation
High Costs of Mechanical Ventilation • Nationwide costs for mechanical ventilation in 1999 were in the range of $45 billion • Ventilator dependent patients have costs that are 8-9 times those of medical-surgical floor patients • Growth in utilization of mechanical ventilation is due to increased use among elderly with chronic conditions • leads to the question whether differential utilization of resources and outcomes are age-specific or due to delivery system changes
How does Delivery System Changes Affect Health Outcomes? • Managed care delivery is associated with lower levels of critical care resource utilization than traditional delivery and financing • Results are mixed whether reduction is due to financial incentives of managed care organization or severity of illness • Which delivery system, managed care or traditional delivery and financing, is more efficient in utilizing these critical care resources?
Study Goals • Study investigates the impact of managed care on hospital survival for critically ill patients requiring mechanically ventilation who are discharged under DRG 483 in New York State during 1992-1996. • Research Questions: • Are improved survival rates among managed care patients due to self-selection or the elimination of ineffective care in the inpatient setting? • Do delivery system changes or clinical characteristics have a greater influence over the health outcomes for this subpopulation?
Data Sources • Hospital Characteristics from the Bureau of Health Economics, NYS Department of Health • Teaching status, number of beds, location • State-wide analysis uses New York Statewide Planning and Research Cooperative System (SPARCS) data base for 1992-1996 under all-payer system • Demographic, clinical, discharge disposition and payor data collected for population of 1,456 patients managed care adults and 32,337 non-managed care adults aged 19-95 discharged under from hospitals under DRG 483, “tracheostomy except for mouth, larynx and pharynx disorder”
Sample Frame Exclusions • Sample does not include patients: • With pre-existing tracheostomy • Who were over 95 years of age due to small numbers • With hospital stay over 90 days • Biologically implausible that events occurring at the time of tracheostomy would have longer-lasting effects • Discharged after 1996 • No confounding from affects from competitive reimbursement regime under the NY Health Care Reform Act enacted in 1997.
Preliminary Statistical Analyses • All conditions and procedures that were present in more than 3.5% of patients were examined with bivariate analysis (2 x 2 contingency tables) to test for an association with mortality • Where possible, similar diagnostic codes were grouped together for the final analysis • Comorbid conditions and procedures associated with a 1.5 times greater risk of mortality than the general subpopulation were obtained from ICD-9 codes (principal and secondary) • Preliminary inpatient survival assessments using Kaplan-Meier curves • Allowed for assessment of proportionality of hazards prior to entry in a multivariate Cox Proportional Hazards Model (PH)
--------Preliminary Statistical Analyses • : • age: linear, quadratic and cubic forms • demographics: dummy variables for race, gender, location • clinical risk factors: dummy variables for high frequency and high mortality diagnoses. Disorders of fluid, electrolyte, and acid-based balance, other bacterial pneumonia, pneumonia, organism unspecified, and pleurisy • admission type: dummy variable for emergency, urgent admission • payer classes: dummy variables for payment source (i.e., selfpay, various insurance combinations) • MCO: dummy variable for managed care participation, % MCO in hospital of discharge • HCRA: dummy variable competitive regime enactment • Length of stay • Teaching: teaching status of hospital of discharge
Profile of DRG 483 and DRG 475 Hospital Survivors in 1995-1999 in New York State • DRG 483 survivors are more likely to be male, have more elective admissions, and have long hospital stays averaging 63 days. • DRG 475 survivors are more likely to be female, Hispanic, have more emergency admissions, and have moderate hospital stays of 17 days • No statistically significant differences between DRG 483 and DRG 475 survivors in managed care coverage and commercial/self-insurance class, upstate location, and most frequent age range of 36-50
Profile of Survivors in DRG 483 and DRG 475 Pre- and Post-NYS Health Care Reform Enactment of 1996 • Pre-HCRA enactment • DRG 483 survivors are equally likely to be MCO and non-MCOs, with 30% of survivors discharged to SNFs • DRG 475 survivors are more likely to be in MCO, with 16% of survivors discharged to SNFs • Post-HCRA enactment • DRG 483 survivors are more likely to be in MCO, with 44% of survivors discharged to SNFs • The greatest proportion of survivors occurs in 1999 • Regardless of MCO status, more survivors are seen post-HCRA • DRG 475 survivors are more likely to be in non-MCO, with 25% of survivors discharged to SNFs • The greatest proportion of survivors occurs in 1997-1999
Skilled Nursing Facility Discharge Rates for DRG 483 and DRG 475 by Year
Competitive Hospital Reimbursements and Payer Status are Major Determinants of Hospital Survival for DRG 483 • Increased likelihood of survival seen for: • Competitive reimbursement regime • MCO discharges under HCRA • Decreased likelihood of survival seen for: • Medicare payment • Non-elective admissions • Statistically significant predictors but do not contribute to increased risk of survival: • MCO status • Hospital teaching status • Length of stay
Competitive Hospital Reimbursements and Payer Status are Major Determinants of Discharges to Skilled Nursing Facilities for DRG483 • Results of two-stage probit model predicting likelihood of SNF discharges for survivors: • Significant increases in likelihood of SNF discharges for: • Competitive reimbursement regime • Medicaid payment • NYC location • Statistically significant predictors but do not contribute to increased risk of discharge location: • MCO status • Length of stay • Est. survival likelihood
Clinical Factors are Major Determinants of Hospital Survival for DRG 475 • Increased likelihood of survival seen for: • Non-elective admissions • Chronic airway obstruction • Decreased likelihood of survival seen for: • Most other high-risk diagnose • Statistically significant predictors but do not contribute to increased risk of survival: • Competitive reimbursement regime • MCO status • Hospital teaching status • Length of stay
Competitive Hospital Regime and Payer Status are Major Determinants of Discharges to Skilled Nursing Facilities for DRG 475 Survivors • Results of two-stage probit estimation predicting likelihood of SNF discharges for survivors: • Increases in SNF discharges seen for: • Competitive reimbursement regime • Medicaid payment • Hospital volume • Most high-risk diagnoses • Statistically significant predictors but do not contribute to increased risk of discharge location: • MCO status • Length of stay • Est. survival prob.
Discussion • Models fit the data well and indicate that competitive hospital market leads to increased shifting to other venues of care for high-cost critical care patients • State-level administrative data can provide indication of impact of system changes on management of patients • Limitations include: • Lack of information concerning specific changes in reimbursement rates by payer under competition • Lack of information concerning intervention by case management and social work to facilitate discharge planning • Unclear what proportion of discharges to other venues are clinically appropriate or due to cost pressures
Clinical Excellence must be Combined with Cost Control • Managed care does not uniquely impact the likelihood of survival nor skilled nursing facility discharges for survivors among DRG 483 and DRG 475 discharges • No unique evidence that managed care preferentially selects patients nor favorably manages discharges on the state-level • Competitive reimbursement regime under HCRA of 1996 indicates trends of increased hospital survival and increased cost-shifting to skilled nursing facilities for survivors among both DRGs • Differential reimbursements under Medicare for hospital and skilled nursing facilities may lead to increased discharges for LTC settings under competition • Critical care services delivered to older persons with chronic illness are facing greater scrutiny but clinical outcomes also need to be considered • more emphasis should be placed on multidisciplinary management teams