Estimating standard errors for life expectancies based on complex survey data with mortality follow-up: A case study using the National Health Interview Survey Linked Mortality Files.

Life expectancy is an important measure for health research and policymaking. Linking individual survey records to mortality data can overcome limitations in vital statistics data used to examine differential mortality by permitting the construction of death rates based on information collected from respondents at the time of interview and facilitating estimation of life expectancies for subgroups of interest. However, use of complex survey data linked to mortality data can complicate the estimation of standard errors. This paper presents a case study of approaches to variance estimation for life expectancies based on life tables, using the National Health Interview Survey Linked Mortality Files. The approaches considered include application of Chiang's traditional method, which is straightforward but does not account for the complex design features of the data; balanced repeated replication (BRR), which is more complicated but accounts more fully for the design features; and compromise, 'hybrid' approaches, which can be less difficult to implement than BRR but still account partially for the design features. Two tentative conclusions are drawn. First, it is important to account for the effects of the complex sample design, at least within life-table age intervals. Second, accounting for the effects within age intervals but not across age intervals, as is done by the hybrid methods, can yield reasonably accurate estimates of standard errors, especially for subgroups of interest with more homogeneous characteristics among their members.

The public-use National Health Interview Survey linked mortality files: methods of reidentification risk avoidance and comparative analysis.

The National Center for Health Statistics (NCHS) conducts mortality follow-up for its major population-based surveys. In 2004, NCHS updated the mortality follow-up for the 1986-2000 National Health Interview Survey (NHIS) years, which because of confidentiality protections was made available only through the NCHS Research Data Center. In 2007, NCHS released a public-use version of the NHIS Linked Mortality Files that includes a limited amount of perturbed information for decedents. The modification of the public-use version included conducting a reidentification risk scenario to determine records at risk for reidentification and then imputing values for either date or cause of death for a select sample of records. To demonstrate the comparability between the public-use and restricted-use versions of the linked mortality files, the authors estimated relative hazards for all-cause and cause-specific mortality risk using a Cox proportional hazards model. The pooled 1986-2000 NHIS Linked Mortality Files contain 1,576,171 records and 120,765 deaths. The sample for the comparative analyses included 897,232 records and 114,264 deaths. The comparative analyses show that the two data files yield very similar results for both all-cause and cause-specific mortality. Analytical considerations when examining cause-specific analyses of numerically small demographic subgroups are addressed.

Medicare claims versus beneficiary self-report for influenza vaccination surveillance.

BACKGROUND: Although self-reported influenza vaccination status is routinely used in surveillance to estimate influenza vaccine coverage, Medicare data are becoming a promising resource for influenza surveillance to inform vaccination program management and planning. PURPOSE: To evaluate the concordance between self-reported influenza vaccination and influenza vaccination claims among Medicare beneficiaries. METHODS: This study compared influenza vaccination based upon Medicare claims and self-report among a sample of Medicare beneficiaries (N=9,378) from the 2011 Medicare Current Beneficiary Survey, which was the most recent year of data at the time of analysis (summer 2013). Sensitivity, specificity, positive predictive value, and negative predictive value were calculated using self-reported data as the referent standard. Logistic regression was used to compute the marginal mean proportions for whether a Medicare influenza vaccination claim was present among beneficiaries who reported receiving the vaccination. RESULTS: Influenza vaccination was higher for self-report (69.4%) than Medicare claims (48.3%). For Medicare claims, sensitivity=67.5%, specificity=96.3%, positive predictive value=97.6%, and negative predictive value=56.7%. Among beneficiaries reporting receiving an influenza vaccination, the percentage of beneficiaries with a vaccination claim was lower for beneficiaries who were aged <65 years, male, non-Hispanic black or Hispanic, and had less than a college education. CONCLUSIONS: The classification of influenza vaccination status for Medicare beneficiaries can differ based upon survey and claims. To improve Medicare claims-based surveillance studies, further research is needed to determine the sources of discordance in self-reported and Medicare claims data, specifically for sensitivity and negative predictive value.

Role of genetic and environmental factors in the increased blood pressures of Bolivian blacks.

The tendency toward hypertension or higher blood pressure is more common in blacks than whites. The factors that account for these differences are attributed to both environmental and genetic factors. To clarify this issue, an anthropological study of black and nonblack populations in the lowland village of Chicaloma, northeastern Bolivia at a midaltitude of 1,800 m was conducted. The study included 159 subjects, of which 79 were black and 80 were nonblack, 17-78 years. The study suggests the following: (1) the socioeconomic status of blacks as measured by an ownership index is greater than that of nonblacks, (2) blacks had higher average systolic and diastolic blood pressures than nonblacks and showed an age-associated increase in blood pressures, (3) the prevalence of hypertension was higher for blacks (7-6%) than nonblacks (1.3%), but three times lower than among blacks in the United States, (4) skin reflectance is inversely related to blood pressures so that contrary to what has been suggested the darker the skin color, the higher the blood pressures even at comparable levels of affluence. These findings together suggest that genetic factors predispose black individuals to increased blood pressures, but the expression of clinical hypertension is influenced by adverse unaccounted environmental factors. Am. J. Hum. Biol. 11:489-498, 1999. Copyright 1999 Wiley-Liss, Inc.

Health characteristics of Medicare traditional fee-for-service and Medicare Advantage enrollees: 1999-2004 National Health and Nutrition Examination Survey linked to 2007 Medicare data.

BACKGROUND: National Health and Nutrition Examination Survey (NHANES) records have been linked to health care use and expenditure information from Medicare records. Claims data are generally available only for traditional fee-for-service (FFS) enrollees and not for Medicare Advantage enrollees. Differences in health characteristics between Medicare Advantage and traditional FFS enrollees could affect conclusions from analyses of the linked files that are restricted to traditional FFS enrollees. METHODS: Data from the 1999-2004 NHANES linked to the 2007 Medicare enrollment data were analyzed. Using examination and interview data collected in NHANES, we compared health characteristics of Medicare beneficiaries aged 65 and over at the NHANES interview by their type of Medicare enrollment in 2007. RESULTS: We found that the overall percentage of Medicare beneficiaries who had hypertension at the time of the NHANES medical examination was lower for Medicare Advantage enrollees compared with traditional FFS enrollees; this was found for the non-Hispanic white population but not for other race and ethnicity groups. We found no statistically significant differences between Medicare Advantage and traditional FFS enrollees overall or within race and ethnicity groups for other health characteristics that were measured or reported at the time of the NHANES interview or medical examination in 1999-2004. CONCLUSIONS: Despite finding no large differences in health characteristics by Medicare enrollment in this analysis, users of the National Center for Health Statistics Medicare linked files should consider potential differences in health characteristics between Medicare Advantage and traditional FFS enrollees that could influence results limited to traditional FFS beneficiaries only.

Iron deficiency in infancy predicts altered serum prolactin response 10 years later.

Serum prolactin may reflect CNS dopaminergic function. Because iron deficiency (ID) alters brain dopamine in rats, serum prolactin levels were previously investigated in infants with varied iron status. High serum prolactin levels correlated with behaviors typical of chronic ID. The objective of this study was to determine the effect of infant iron status on serum prolactin levels after a stressor in early adolescence. One hundred fifty-nine of 191 children enrolled in infancy (chronic ID, n = 46; good iron comparison group, n = 113) had serum prolactin measurements after catheter placement at 11-14 y of age. Serum prolactin levels were compared by sex, pubertal status and infant iron status and the pattern of change over time was compared by infant iron status controlling for pubertal stage and background factors. Males and less mature adolescents had lower serum prolactin concentrations than females and more mature adolescents. Controlling for these factors, the serum prolactin response pattern differed significantly by infant iron status. Serum prolactin declined earlier for the chronic ID group. In conclusion, an altered serum prolactin response pattern was observed 10 y after chronic ID in infancy and may suggest a long-lasting effect of ID on the regulation of prolactin.