The Relationship between the Level of Serum Creatinine, Modified Diet and Renal Disease Formula, Cockcroft-Gault Formula, and Renal Tubulointerstitial Lesion

Objective: This study investigated the relationship between the levels of serum creatinine (SCr), the estimated glomerular filtration rate (eGFR), and the degree of tubulointerstitial injury. Methods: A total of 511 patients of Zhongshan hospital in China were hospitalized due to physical abnormalities and diagnosed with kidney disease by renal biopsy. The clinical and pathological data were retrospectively analyzed. The level of SCr was determined in all patients, and the eGFR was calculated with modification of diet in renal disease and Cockcroft-Gault formulae, whereas the renal histopathology was quantified according to the Katafuchi semi-quantitative standards. Results: With the aggravation of tubulointerstitial injury, SCr level increased and eGFR decreased gradually. The degree of tubulointerstitial lesion showed a positive correlation with SCr level and negative correlation with Cockcroft-Gault formula and modification of diet in renal disease (r = 0.627, -0.649, -0.626; p < 0.001). When the SCr was in the normal range, above 90% of the patients had various degrees of tubulointerstitial damage and 12.2% of the patients had moderate-to-severe tubulointerstitial lesions. The correlation between SCr level and tubulointerstitial damage became weak. Conclusions: The morphologic changes of tubulointerstitium are closely linked with renal function, but incompletely parallel. SCr in the abnormal range could be used to diagnose tubulointerstitial injury well. However, when the level of SCr was in the so-called normal range, eGFR by the modification of diet in renal disease or Cockcroft-Gault formula may be preferred to assess renal tubulointerstitial injury.