Index to predict 5-year mortality of community-dwelling adults aged 65 and older using data from the National Health Interview Survey.
BACKGROUND
Prognostic information is becoming increasingly important for clinical decision-making.


OBJECTIVE
To develop and validate an index to predict 5-year mortality among community-dwelling older adults.


METHODS
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
This validated mortality index can be used to account for participant life expectancy in analyses using NHIS data.
Schonberg
Mara A
MA
Division of General Medicine and Primary Care, Department of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, 1309 Beacon, Brookline, Boston, MA, USA. mschonbe@bidmc.harvard.edu
Davis
Roger B
RB
McCarthy
Ellen P
EP
Marcantonio
Edward R
ER
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006305:Health Status Indicators; D006306:Health Surveys; D006801:Humans; D008297:Male; D009026:Mortality / Q000639:trends; D015203:Reproducibility of Results; D012111:Residence Characteristics; D013223:Statistics as Topic / Q000592:standards*; D015996:Survival Rate / Q000639:trends; D014481:United States