Index to Predict 5-Year Mortality of Community-Dwelling Adults Aged 65 and Older Using Data from the National Health Interview Survey
- 508 Downloads
Prognostic information is becoming increasingly important for clinical decision-making.
To develop and validate an index to predict 5-year mortality among community-dwelling older adults.
DESIGN AND PARTICIPANTS
A total of 24,115 individuals aged >65 who responded to the 1997-2000 National Health Interview Survey (NHIS) with follow-up through 31 December 2002 from the National Death Index; 16,077 were randomly selected for the development cohort and 8,038 for the validation cohort.
39 risk factors (functional measures, illnesses, behaviors, demographics) were included in a multivariable Cox proportional hazards model to determine factors independently associated with mortality. Risk scores were calculated for participants using points derived from the final model’s beta coefficients. To evaluate external validity, we compared survival by quintile of risk between the development and validation cohorts.
Seventeen percent of participants had died by the end of the study. The final model included 11 variables: age (1 point for 70-74 up to 7 points for >85); male: 3 points; BMI <25: 2 points; perceived health (good: 1 point, fair/poor: 2 points); emphysema: 2 points; cancer: 2 points; diabetes: 2 points; dependent in instrumental activities of daily living: 2 points; difficulty walking: 3 points; smoker-former: 1 point, smoker-current: 3 points; past year hospitalizations-one: 1 point, >2: 3 points. We observed close agreement between 5-year mortality in the two cohorts; which ranged from 5% in the lowest risk quintile to 50% in the highest risk quintile in the validation cohort.
This validated mortality index can be used to account for participant life expectancy in analyses using NHIS data.
KEY WORDSmortality prediction life expectancy prevention older adults
We would like to thank Long Ngo, PhD, from the Division of General Medicine and Primary Care, Department of Medicine, at Beth Israel Deaconess Medical Center and Harvard Medical School for his help in discussions of the analysis plan. Dr. Mara Schonberg was supported by a National Institute on Aging K23 award (K23AG028584).
Conflict of Interest Statement
- 1.US Census Bureau. Current Population Survey, July 2002. Washington, DC: US. Census Bureau; 2002. Accessed at www.census.gov in July 13, 2009.
- 2.Huang ES, Zhang Q, Gandra N, Chin MH, Meltzer DO. The effect of comorbid illness and functional status on the expected benefits of intensive glucose control in older patients with type 2 diabetes: a decision analysis. Ann Intern Med. 2008;141:11–9.Google Scholar
- 3.National Health Interview Survey. National Center for Health Statistics. [Public use data file and documentation]. Available at: http://www.cdc.gov/nchs/nhis. Accessed July 13, 2009.
- 10.Kapp JM, LeMaster JW, Zweig SC, Mehr DR. Physician recommendations for mammography in women aged 70 and older. J Am Geriatr Soc. 2008;2100-2106.Google Scholar
- 20.Horm J. Multiple causes of death for the national health interview survey. Record linkage techniques—Proceedings of an International Workshop and Exposition, 1997: National Research Council, Washington D.C., 1997.Google Scholar
- 24.Hosmer DW Jr, Lemeshow S. Applied Logistic Regression. 2nd ed. New York: John Wiley & Sons, Inc.; 2000:282.Google Scholar
- 25.Arias E. United States Life Tables, 2004. National Vital Statistics Reports. 2007;56:13.Google Scholar