Patient Demographics and Biopsy Safety
A total of 304 renal biopsies were performed during the study period. The
cohort comprised 189 females (62.2%) and 115 males (37.8%). Patients were
referred from 13 of Egypt's 27 governorates, predominantly from Dakahlia,
Gharbia, Sharqia, Damietta, and Beheira. Native kidney biopsies accounted for
291 cases, with 13 transplant kidney biopsies.
The procedure demonstrated excellent safety, with complication rates
remaining very low. Only 0.7% (n=2) required blood transfusion due to large
hematomas, and all complications were self-limited without requiring surgical
or radiological intervention. Most biopsies yielded adequate tissue for
diagnosis, with a mean glomerular count of 22±12; only 5 biopsies were
considered limited.
Clinical Characteristics and Indications
Common comorbidities included hypertension (42.4%, n=129), diabetes
mellitus (11.2%, n=34), hepatitis C virus seropositivity (6.6%, n=20), and
family history of kidney disease (3.3%, n=10). The median eGFR at presentation
was 32.7 mL/min/1.73m² (IQR: 9.38–80.88).
The primary indications for biopsy were isolated proteinuria (33.2%,
n=101) and unexplained renal impairment combined with proteinuria (31.6%,
n=96). Isolated unexplained renal impairment accounted for 27.0% (n=82) of
cases. Less frequent indications included rapidly progressive
glomerulonephritis (RPGN) (3.3%, n=10), the triad of renal impairment,
proteinuria, and hematuria (1.6%, n=5), isolated hematuria (1.6%, n=5), and
combined proteinuria and hematuria without renal impairment (1.3%, n=4).
Histopathological Spectrum
Lupus nephritis (LN) was the most common diagnosis, representing 28.8% of
cases, with Class IV predominating (73%) over Class III (27%). The second most
frequent diagnosis was membranoproliferative glomerulonephritis (MPGN) (17.6%),
followed by diffuse glomerulosclerosis (13.6%), focal segmental
glomerulosclerosis (FSGS) (11.2%), tubulointerstitial nephritis (TIN) (7.0%),
mesangial proliferative GN (6.4%), membranous nephropathy (4.8%), crescentic GN
(4.0%), and minimal change disease (MCD) (2.4%).
Among diabetic patients, 70% had diabetic nephropathy on biopsy, while
30% had other glomerulonephritides, primarily MPGN and LN. Gender distribution
varied by diagnosis: LN demonstrated marked female predominance (female-to-male
ratio 4.8:1), MPGN showed equitable gender distribution (~1:1), and MCD, FSGS,
and membranous nephropathy were more common in males.
Clinicopathological Correlations
Sonographic Assessment: Pre-biopsy sonographic evaluation by nephrologists revealed
statistically significant correlations with histopathological markers of
chronicity. The echogenicity index demonstrated strong positive correlations
with interstitial fibrosis percent (r=0.498, p<0.001), tubular atrophy
percent (r=0.468, p<0.001), and total percent of glomerulosclerosis
(r=0.412, p<0.001). Additionally, echogenicity correlated with vascular
changes (r=0.273, p=0.002), often indicating arteriolar hyalinosis or
hypertensive vascular changes.
Kidney Function: eGFR and serum creatinine at presentation exhibited the strongest
correlations with chronic damage parameters, including tubular atrophy percent
(r=-0.565/0.561, p<0.001), interstitial fibrosis percent (r=-0.616/0.612,
p<0.001), and glomerulosclerosis percent (r=-0.358/0.364, p<0.001).
Proteinuria: Neither quantitative proteinuria nor dipstick analysis correlated with
chronic damage scores (interstitial fibrosis and tubular atrophy [IFTA],
glomerulosclerosis). However, quantitative proteinuria showed a positive
correlation with detached podocytes (r=0.670, p=0.024).
Hematuria: Most patients (63.3%) exhibited mild hematuria (<20 RBCs/hpf), while
13.5% had significant hematuria (>50 RBCs/hpf). Hematuria correlated
specifically with active inflammatory lesions, particularly crescent formation
(r=0.218, p=0.022), but not with chronic damage markers.
Hypertension and Age: Both hypertension and advancing age demonstrated significant
associations with chronic sclerotic damage—including tubular atrophy,
interstitial fibrosis, global glomerulosclerosis, and vascular changes—rather
than active inflammatory lesions. Older patients showed higher prevalence of
diabetic nephropathy and hypertensive nephrosclerosis (p=0.018).
Hepatitis C Virus: HCV-positive patients demonstrated increased likelihood of MPGN
(p=0.009) and cryoglobulinemic features.
