The incidence of biopsy-proven glomerulonephritis in Cairo University, Egypt: a 5-year study

Sir,

The incidence of biopsy-proven glomerulonephritis (GN) varies in different geographical areas and is affected by socio-economic conditions, race, differences in genetic susceptibility and environmental exposure. Recent studies suggested a changing pattern of incidence of GN in different parts of the world [1,2]. For instance, the incidence of end-stage renal disease (ESRD) as a result of focal segmental glomerulosclerosis (FSGS) has increased 11-fold in the past two decades in a recent study [2].

Our study aimed to obtain a comprehensive review of the incidence of biopsy-proven glomerulonephritis in Cairo University, Egypt, over the last 5 years. We analysed the clinical and pathological data of all renal biopsy samples that were obtained during the period from July 2003 to 2008. Age, gender, indication of renal biopsy and the pathological findings were recorded for analysis.

A total of 924 renal biopsy samples were referred for pathological assessment during the period of the study. The monthly incidence of biopsy-proven GN was 15.4 (range 13–19). Proliferative GN was reported in 497 cases (53.78%) and non-proliferative GN was reported in 427 cases (46.22%). Lupus nephritis was reported in 264 cases (28.57%). The female/male ratio was 221/41, 70% of lupus patients aged 18–45 years and 85% had renal impairment (mean serum creatinine was 3.21 ± 4.09 mg/dl). The common glomerular pathologies in patients with lupus nephritis were the proliferative classes II–IV (28.78, 30.30, 27.65%, respectively).

Morphologically, FSGS was the most frequent cause of GN (21.21%) followed by mesangial proliferative GN (18.93%), diffuse proliferative GN (13.96%), focal proliferative GN (12.77%) and membranous GN (10.93%) (Table 1). In females, mesangial proliferative, focal proliferative GN and diffuse proliferative GN were the predominant pathological findings, and in males FSGS, diffuse proliferative GN and mesangial proliferative GN were predominant. In those aged <18, mesangial proliferative GN, minimal change disease and FSGS were more prevalent compared to adults. Figure 1 shows the frequency of GN in patients with renal insufficiency.

Table 1.

Incidence of biopsy proven GNs in the study group

Lupus nephritis (LN-GN): 264 Cases (28.57%)

Focal segmental glomerulosclerosis (FSGS): 185 Cases (20.02%)

Mesangial proliferative GN: 97 cases (10.49%)

Minimal change disease (MCD): 79 Cases (8.55%)

Membranoproliferative GN (MPGN): 68 cases (7.36%)

Membranous Nephropathy (MGN): 65 cases (7.03%)

Amyloid: 51 cases (5.52%)

Diffuse Proliferative GN: 48 cases (5.20%)

Focal Proliferative GN: 34 cases (3.68%)

Diabetic Glomerulosclerosis: 2 cases (0.22%)

Fig. 1.

Incidence of GNs in patients with renal insufficiency [352 cases (38.09%)]. We conclude that FSGS and proliferative GN (SLE and others) were the predominant forms of GN in the population of the study. Compared to other Arab countries, FSGS was the predominant GN in two studies coming from Saudi Arabia [3] and Kuwait [4]. MGN was the predominant GN in two reports from United Arab Emirates and Iran [5,6]. Our results could be explained by high incidence of lupus nephritis among the study subjects as well as the relatively young age of the study group. Further multicentre studies with larger sample size from different parts of the country would give more accurate information on the incidence and frequency of GNs in Egypt.

Conflict of interest statement. None declared.