Statistical methods used in the calculation of geriatric reference intervals: a systematic review

Area of Science:

• Clinical Chemistry
• Biostatistics
• Geriatric Medicine

Background:

• Geriatric reference intervals (RIs) are scarce and seldom utilized due to challenges in defining healthy elderly populations.
• Appropriate statistical methodologies are crucial for establishing reliable health-associated reference values.

Purpose of the Study:

• To critically examine the statistical methods employed in the calculation of geriatric reference intervals (RIs).

Main Methods:

• A systematic literature search was conducted on EMBASE and Medline (1989-2014) for English primary articles.
• Studies were included if they reported clinical chemistry tests on blood fractions from individuals aged 65 years and older and calculated RIs for this group.

Main Results:

• Of 64 identified articles, 78.1% described RI calculation methods, with parametric (42.2%) and non-parametric (21.9%) being most common.
• Outlier detection and significance testing for partitions were infrequently used. Only 14.1% of studies adhered to CLSI guideline EP28-A3c for RI estimation.

Conclusions:

• Significant variability exists in statistical methods for geriatric RI calculation and partitioning, with many studies lacking adequate methodological descriptions.
• Insufficient sample sizes and population heterogeneity pose analytical challenges. Geriatric RIs require careful evaluation before clinical application due to potential calculation inaccuracies.