BIS (Berlin Initiative Study)

Adult2012

Elderly-specific equation for patients ≥70 years

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Calculate BIS

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For educational and clinical reference use. Interpret results in clinical context.

Formula

eGFR=3736×SCr−0.87×age−0.95×0.82[female]\text{eGFR} = 3736 \times \text{SCr}^{-0.87} \times \text{age}^{-0.95} \times 0.82^{[\text{female}]}

Formula constants

SymbolDescriptionValue
3736Base coefficient
−0.87Creatinine exponent
−0.95Age exponent
Sex factorSex-dependent multiplier
Female:0.82
Male:1.00
ScrS_{cr}inputSerum creatininemg/dL
AgeinputPatient ageyears

Required inputs

AgeSexCreatinine

Validated age range

70 to 120 years

Limitations

  • Designed specifically for elderly patients ≥70 years
  • May be less accurate in younger patients
  • Developed in German Caucasian elderly cohort
  • No race coefficient — not validated in diverse populations

Clinical notes

  • Specifically designed for elderly patients ≥70 years
  • Better performance than CKD-EPI in elderly population
  • Developed in German elderly cohort (no race coefficient)
  • May be more accurate for elderly patients
  • Limited validation outside elderly German population

References

  • [1]Schaeffner ES, Ebert N, Delanaye P, et al. Two novel equations to estimate kidney function in persons aged 70 years or older. Ann Intern Med. 2012;157(7):471-481. doi:10.7326/0003-4819-157-7-201210020-00003
  • [2]Ebert N, Jakob O, Gaedeke J, et al. Prevalence of reduced kidney function and albuminuria in older adults: the Berlin Initiative Study. Nephrol Dial Transplant. 2017;32(6):997-1005. doi:10.1093/ndt/gfw079

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