Major Declines in Severe Cognitive Impairment in the U.S. Elderly Population: New Estimates from the 1984 and 2004 National Long Term Care Survey
Eric Stallard, Duke University
Purpose: To estimate age-standardized 20-year changes in severe cognitive impairment (SCI) among the U.S. elderly using the HIPAA CI trigger. Methods: SCI-1 was defined as 3+ SPMSQ errors, caregiver report of Alzheimer’s disease/dementia, or similar problems, with concurrent substantial supervision; SCI-2 and SCI-3 were defined similarly, with SPMSQ cut-points = 4+ and 5+ errors, respectively. Results: Overall prevalence rates were 9.2% and 6.7% for SCI-1 in 1984 and 2004, respectively. Age-standardized rates of decline were 2.74%/yr. for SCI-1 (t = 15.53), 2.66%/yr for SCI-2 (t = 13.45), and 2.58%/yr for SCI-3 (t = 12.16). Sex differences in prevalence were large (e.g., 4.7% (M) v. 8.1% (F), SCI-1, 2004), but the rates of decline were similar (e.g., 2.85%/yr. [M; t = 8.15] v. 2.59%/yr. [F; t = 12.75], SCI-1, 2004). Conclusions: SCI exhibited substantively important and highly statistically significant declines among the U.S. elderly during the 20-year period 1984–2004.