Evaluation of bipolar lengths of the kidneys in healthy Sri Lankan adults in view of assessing the need for nomograms

Introduction:  Renal sizes are of immense use to diagnose renal pathologies. As ethnic variations are known to influence renal sizes, we aimed to assess the ethnic variations in bipolar renal length (RL) and kidney to body height ratio (KBR) of a young adult Sri Lankan population.

Methods: Healthy adults were recruited, by excluding subjects with previous renal surgeries, renal diseases, or other chronic illnesses. Bilateral RLs were measured sonographically.

Results: The study sample consisted of 215 individuals (100 females) with an age range of 19-36 years (mean age=24 years). Mean right RL was 9.77±0.78cm; mean left RL was 10.16±0.83cm; mean KBR of the right kidney was 0.60±0.05mm/cm and left kidney was 0.63±0.05mm/cm. Right and left RLs and KBRs of males were 9.82±0.76cm; 10.3±0.78cm and 0.59±0.05mm/cm; 0.62±0.05mm/cm respectively and same parameters in females were 9.71±0.8cm; 10.0±0.9cm and 0.62±0.05mm/cm; 0.64±0.05mm/cm respectively. Irrespective of gender, left RL and KBR were higher than those of the right side (p<0.001). RLs were significantly different (p<0.05) compared to European and North American populations.

Conclusions: This preliminary study can be considered as the first step in establishing age and gender specific reference values for RL and KBR for a Sri Lankan population. Due to ethnic variations, accuracy of using renal nomograms from other populations as reference values raises serious concerns.