The intermountain risk score predicts incremental age-specific long-term survival and life expectancy

Area of Science:

• Medical Informatics
• Biostatistics
• Gerontology

Background:

• The Intermountain Risk Score (IMRS) integrates complete blood count (CBC) and basic metabolic profile (BMP) data with age to estimate mortality risk.
• Individualizing risk prediction requires understanding how IMRS weightings for short-term mortality correlate with long-term survival.

Purpose of the Study:

• To evaluate if IMRS weightings for 1-year mortality predict age-specific survival over a decade.
• To assess the IMRS's utility in stratifying long-term mortality risk within age-defined subgroups.

Main Methods:

• Calculated sex-specific 1-year IMRS values for general medical patients (1999-2005).
• Randomly divided the cohort into examination (60%) and validation (40%) samples.
• Established age-specific risk thresholds and compared survival and life expectancy across low-, moderate-, and high-risk IMRS categories over 7.3 ± 1.8 years of follow-up.

Main Results:

• Higher average IMRS was associated with increased mortality across all age/sex strata (P < 0.001).
• Incremental decreases in survival and life expectancy were observed with higher IMRS risk categories across all age groups (HRs 2.5-8.5, P < 0.001).
• Significant stratification of survival and life expectancy by IMRS risk level was confirmed in both examination and validation samples.

Conclusions:

• The IMRS effectively stratifies age-specific mortality risk over more than a decade.
• IMRS demonstrates utility for research, clinical decision-making, preventive care, and quality improvement initiatives.
• A web calculator is available for practical application of the IMRS.