/* STATA Code for calculating U25 eGFR */ /* Reference: Pierce CB, Muñoz A, Ng DK, Warady BA, Furth SL, Schwartz GJ. Age- and sex-dependent clinical equations to estimate glomerular filtration rates in children and young adults with chronic kidney disease. Kidney Int. 2021 Apr;99(4):948-956. doi: 10.1016/j.kint.2020.10.047. Epub 2020 Dec 8. [ PMID: 33301749]*/ /* Online calculators access: https://ckid-gfrcalculator.shinyapps.io/eGFR/ or https://qxmd.com/calculate/calculator_822/ckid-u25-egfr-calculator # Input: VARIABLE DESCRIPTION female sex, 0 for male, 1 for female age age, years (value between 1 to 25 years) ht_m height, meters (value between 0.6 and 2 m) sCr Serum creatinine, mg/dL (value between 0.1 and 10 mg/dL) cyc_ifcc IFCC-calibrated Cystatin C, mg/dL (value between 0.2-8 and IFCC-calibrated. A non-calibrated Siemens cystatin C value should be multiplied by 1.17 to approximate its equivalent IFCC-calibrated value.) Output: VARIABLE DESCRIPTION eGFRU25scr U25 eGFR based on serum creatinine only eGFRU25cys U25 eGFR based on IFCC-calibrated cystatin c only eGFRU25ave U25 eGFR based on serum creatinine and IFCC-calibrated cystatin c as average of eGFRU25scr and eGFRU25cys */ infile ID female age ht_m sCr cyc_ifcc using "filepath\U25eGFRtest.dat", clear gen ckidKscr = 39.0 * (1.008^(age-12)) if (female==0 & age< 12) replace ckidKscr = 39.0 * (1.045^(age-12)) if (female==0 & age>= 12 & age< 18) replace ckidKscr = 50.8 if (female==0 & age>= 18) replace ckidKscr = 36.1 * (1.008^(age-12)) if (female==1 & age< 12) replace ckidKscr = 36.1 * (1.023^(age-12)) if (female==1 & age>= 12 & age< 18) replace ckidKscr = 41.4 if (female==1 & age>= 18) gen eGFRU25scr= ckidKscr * ht_m / sCr gen ckidKcyc = 87.2 * (1.011^(age-15)) if (female==0 & age< 15) replace ckidKcyc = 87.2 * (0.960^(age-15)) if (female==0 & age>= 15 & age< 18) replace ckidKcyc = 77.1 if (female==0 & age>= 18) replace ckidKcyc = 79.9 * (1.004^(age-12)) if (female==1 & age< 12) replace ckidKcyc = 79.9 * (0.974^(age-12)) if (female==1 & age>= 12 & age< 18) replace ckidKcyc = 68.3 if (female==1 & age>= 18) gen eGFRU25cyc= ckidKcyc / cyc_ifcc gen eGFRU25average= (eGFRU25scr + eGFRU25cyc) / 2 list