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Jay Bhattacharya

Publications and source records attributed to Jay Bhattacharya.

5 recordsLinked to original sources
PubMed2006

Estimating probit models with self-selected treatments.

Outcomes research often requires estimating the impact of a binary treatment on a binary outcome in a non-randomized setting, such as the effect of taking a drug on mortality. The data often come from self-selected samples, leading to a spurious correlation between the treatment and outcome when standard binary dependent variable techniques, like logit or probit, are used. Intuition suggests that a two-step procedure (analogous to two-stage least squares) might be sufficient to deal with this problem if variables are available that are correlated with the treatment choice but not the outcome. This paper demonstrates the limitations of such a two-step procedure. We show that such estimators will not generally be consistent. We conduct a Monte Carlo exercise to compare the performance of the two-step probit estimator, the two-stage least squares linear probability model estimator, and the multivariate probit. The results from this exercise argue in favour of using the multivariate probit rather than the two-step or linear probability model estimators, especially when there is more than one treatment, when the average probability of the dependent variable is close to 0 or 1, or when the data generating process is not normal. We demonstrate how these different methods perform in an empirical example examining the effect of private and public insurance coverage on the mortality of HIV+ patients.

Anti-HIV Agents↗
PubMed2004

Impacts of informal caregiver availability on long-term care expenditures in OECD countries.

OBJECTIVE: To quantify the effects of informal caregiver availability and public funding on formal long-term care (LTC) expenditures in developed countries. DATA SOURCE/STUDY SETTING: Secondary data were acquired for 15 Organization for Economic Cooperation and Development (OECD) countries from 1970 to 2000. STUDY DESIGN: Secondary data analysis, applying fixed- and random-effects models to time-series cross-sectional data. Outcome variables are inpatient or home heath LTC expenditures. Key explanatory variables are measures of the availability of informal caregivers, generosity in public funding for formal LTC, and the proportion of the elderly population in the total population. DATA COLLECTION/EXTRACTION METHOD: Aggregated macro data were obtained from OECD Health Data, United Nations Demographic Yearbooks, and U.S. Census Bureau International Data Base. PRINCIPAL FINDINGS: Most of the 15 OECD countries experienced growth in LTC expenditures over the study period. The availability of a spouse caregiver, measured by male-to-female ratio among the elderly, is associated with a $28,840 (1995 U.S. dollars) annual reduction in formal LTC expenditure per additional elderly male. Availability of an adult child caregiver, measured by female labor force participation and full-time/part-time status shift, is associated with a reduction of $310 to $3,830 in LTC expenditures. These impacts on LTC expenditure vary across countries and across time within a country. CONCLUSIONS: The availability of an informal caregiver, particularly a spouse caregiver, is among the most important factors explaining variation in LTC expenditure growth. Long-term care policies should take into account behavioral responses: decreased public funding in LTC may lead working women to leave the labor force to provide more informal care.

Adult↗
PubMed2003

Forecasting the nursing home population.

OBJECTIVE: To forecast growth in the US nursing home population, as a function of trends in disability and marriage. METHODS: Nursing home residence is modeled as a function of disability status, marital status, and other demographic covariates. Our predictions for nursing home residence are built upon joint forecasts of marriage and disability. We use data from the 1992 to 1996 Medicare Current Beneficiary Surveys, which are individual-level data sets designed to be representative of the US population older than the age of 65. RESULTS: Today's young cohorts will have higher rates and levels of institutionalization than their older counterparts. This will reverse several decades of decline in rates of disability and institutionalization. The nursing home population is likely to be 10-25% higher than would be suggested by a simple extrapolation of past declines in disability. CONCLUSIONS: In recent years, the rate of institutionalization among the elderly has been falling. It is predicted that this trend will reverse itself within the next decade, and that we will see substantial increases in the incidence of institutionalization among the elderly. This result is generated by our prediction of rising disability among the younger cohorts that are beginning to approach old age.

Activities of Daily Living↗
PubMed2002

Role of neck surgery in conjunction with radiation in regional control of node-positive cancer of the oropharynx.

For patients with clinically node-positive oropharynx cancer treated with radiotherapy, planned neck dissection is controversial. We investigated whether neck surgery after radiation reduces nodal recurrence. Between 1970 and 1995, 263 patients at Massachusetts General Hospital received radiotherapy for clinically node-positive base of tongue or tonsil carcinomas. Patients received three different types of treatment: neck surgery followed by radiation (SR)-50 patients; radiation alone (RT)-160 patients; and radiation followed by surgery (RS)-53 patients. Median patient follow-up was 28 months. SR patients have an 84% complete response (CR) rate, RT patients 76%, and RS patients 13%. In multivariate analysis, among patients with a CR, the three treatment groups have the same regional control rates. Among patients with an incomplete response, the RS treatment group is 67% (p < 0.01) and 86% (p < 0.01) less likely to have recurrence than the RT and SR groups, respectively. Neck dissection after radiation therapy improves regional control for patients without a complete clinical response to radiation therapy but not for those with a CR. Despite higher CR rates, neck dissection before radiation confers no regional control benefit. We therefore recommend that primary radiotherapy with neck dissection be reserved for those without a complete clinical response.

Adult↗