A Systematic Review of Glomerular Hyperfiltration Assessment and Definition in the Medical Literature

Abstract

Background and objectives Evaluation of glomerular hyperfiltration (GH) is difficult; the variable reported definitions impede comparisons between studies. A clear and universal definition of GH would help in comparing results of trials aimed at reducing GH. This study assessed how GH is measured and defined in the literature.Design, setting, participants, & measurements Three databases (Embase, MEDLINE, CINAHL) were systematically searched using the terms "hyperfiltration" or "glomerular hyperfiltration". All studies reporting a GH threshold or studying the effect of a high GFR in a continuous manner against another outcome of interest were included.Results The literature search was performed from November 2012 to February 2013 and updated in August 2014. From 2013 retrieved studies, 405 studies were included. Threshold use to define GH was reported in 55.6% of studies. Of these, 88.4% used a single threshold and 11.6% used numerous thresholds adapted to participant sex or age. In 29.8% of the studies, the choice of a GH threshold was not based on a control group or literature references. After 2004, the use of GH threshold use increased (P,0.001), but the use of a control group to precisely define that GH threshold decreased significantly (P,0.001); the threshold did not differ among pediatric, adult, or mixedage studies. The GH threshold ranged from 90.7 to 175 ml/min per 1.73 m 2 (median, 135 ml/min per 1.73 m 2 ).Conclusion Thirty percent of studies did not justify the choice of threshold values. The decrease of GFR in the elderly was rarely considered in defining GH. From a methodologic point of view, an age-and sex-matched control group should be used to define a GH threshold.

Glomerular Hyperfiltration: An Early Marker of Nephropathy in Fabry Disease

“…A systematic review by Cachat et al [43] on the assessment of glomerular hyperfiltratrion shows that 55.6% of examined studies report an HF threshold of 135 mL/min, although definitions range between 90 and 175 mL/min; even if Helal et al [17] restrict the range from 120 to 175 mL/min, both studies clearly evidence that an unanimously accepted definition of HF does not exist.…”

“…In fact, while hyperfiltering, untreated patients may be easily found in type I diabetes, where even reference control groups from previously published studies are reported [43], to select a control group of age-and sex-matched patients in FD is extremely difficult, since the diagnosis of the disease is often delayed and its clinical expression (including HF) is strongly conditioned by the type of mutation, the amount of residual enzymatic activity, and the different levels of Gb3. The actual implementation of early diagnosis of FD DOI: 10.1159/000493469 may allow the recruitment of new patients and provide a control group for HF study in the near future.…”

Effect of weight loss after bariatric surgery on kidney function in a multiethnic Asian population

“…The eGFR cut-off was arbitrarily selected based on National Kidney Foundation Kidney Disease Outcomes Quality Initiative (KDOQI) that states an eGFR o 90 mL/min per 1.73 m 2 is abnormal [16]. It is unknown what defines normal kidney function in the obese patient [17,19,20]. To achieve an 80% probability of detecting a significant change in renal function, power calculations indicated that 10 and 21 patients were required in the eGFR o 90 and 4 90 mL/ min per 1.73 m 2 subgroups, respectively.…”

“…(1) Estimated glomerular filtration rate (eGFR, mL/min per 1.73 m 2 ) using the CKD-EPI formula [9] ¼ [16,17].…”

New insights on glomerular hyperfiltration: a Japanese autopsy study

“…These findings suggest that larger glomeruli have undergone compensatory hypertrophic growth that tends to normalize the total glomerular volume in a kidney (15). Glomerular hypertrophy also occurs with hypertension and obesity, suggesting that increased metabolic and excretory demands can contribute to compensatory glomerular growth (16)(17)(18). Although the effect of increased glomerular volume on glomerular function is unclear (18-21), Denic et al recently found that single-nephron glomerular filtration rate (SNGFR; measured GFR divided by the number of nephrons) in healthy adult kidney donors was fairly constant with regard to age, sex, and height (if < 190 cm) (22).…”