| Abstract|| |
Glomerular diseases continue to be the leading cause of end-stage renal disease (ESRD) globally. Hence, it is important to recognize the pattern of glomerular diseases in different geographical areas in order to understand the patho-biology, incidence and progression of the disorder. Published studies from different centers in Saudi Arabia have reported contradicting results. In this retrospective study, we report our experience at the Armed Forces Hospital, Riyadh, Saudi Arabia. A total of 348 native renal biopsies performed at our center on patients with proteinuria >1 g, hematuria and/or renal impairment during a period of 5 years (between January 2005 and December 2009) were studied by a histopathologist using light microscopy, immunofluorescence and electron microscopy, and were categorized. Results showed that primary glomerular disease accounted for 55.1% of all renal biopsies. The most common histological lesion was focal and segmental glomerulosclerosis (FSGS) (27.6%), followed by minimal change disease (MCD) (17.7%) and membrano-proliferative glomerulonephritis (MPGN) (13.0%). Secondary glomerular disease accounted for 37.9% of the glomerular diseases, with lupus nephritis (LN) being the most common lesion (54.5%), followed by hypertensive nephrosclerosis (22%), post-infectious glomerulonephritis (7.5%), diabetic nephropathy (DN) (6.8%) and vasculitides (4.5%). Four percent of all biopsies turned out to be ESRD while biopsy was inadequate in 2.8% of the cases. In conclusion, our study showed that FSGS was the most common primary GN encountered, while LN was the most common secondary GN. We encountered 14 cases of crescentic glomerulonephritis. Also, the prevalence of MPGN, MCD, IgA nephropathy and membranous GN was many folds higher in males when compared with the Western data. We believe that it is mandatory to maintain a Saudi Arabian Renal Biopsy Registry to understand better the pattern of glomerular disease in the Saudi population and to follow any change in trend.
|How to cite this article:|
Nawaz Z, Mushtaq F, Mousa D, Rehman E, Sulaiman M, Aslam N, Khawaja N. Pattern of glomerular disease in the Saudi population: A single-center, five-year retrospective study. Saudi J Kidney Dis Transpl 2013;24:1265-70
|How to cite this URL:|
Nawaz Z, Mushtaq F, Mousa D, Rehman E, Sulaiman M, Aslam N, Khawaja N. Pattern of glomerular disease in the Saudi population: A single-center, five-year retrospective study. Saudi J Kidney Dis Transpl [serial online] 2013 [cited 2019 Oct 17];24:1265-70. Available from: http://www.sjkdt.org/text.asp?2013/24/6/1265/121288
| Introduction|| |
Glomerular disease is a common cause of endstage renal disease (ESRD) in both developing and developed countries. The pattern of glomerulonephritis (GN) varies widely from country to country and even from region to region within a country, reflecting the possible effects of socio-economic, genetic and environmental factors as well as nephrology practice and facilities available in that locality.
The pattern of GN is not well documented in Saudi Arabia. Many retrospective and few prospective studies have been performed in different regions, the maximum being in the Central Region; the results have shown variable patterns. Moreover, an epidemiological study at the national scale is not available yet.
The current study was performed to show the frequency of occurrence of primary and secondary GN observed in a tertiary care hospital catering to patients from all areas of Saudi Arabia, mainly the central region, Riyadh.
| Materials and Methods|| |
Data pertaining to all native kidney biopsies performed over a period of 5 years from January 2005 to December 2009 in our hospital were collected retrospectively. The total number of biopsies performed was 348, of which the sample was insufficient in 2.8%; the others were analyzed and categorized as primary and secondary GN. The age, gender and adult to child ratio were looked into and analyzed.
All biopsies were performed percutaneously by an automated gun and examined using a light microscope (LM), immonofluorescence (IF) and an electron microscope (EM), and were categorized as per the World Health Organization classification by our histopathologist.
The indications for biopsy included the nephrotic syndrome, the nephritic syndrome, acute renal failure and systemic disease with renal involvement.
| Results|| |
Of the 348 biopsies performed, 176 were on adult males, 127 were on adult females and 45 were on children (cut-off age <15 years); 192 (55.1%) were found to have primary GN, 132 (37.9%) secondary GN, 14 (4%) ESRD and, in 10 (2.8%), the sample was insufficient [Table 1], [Figure 1] and [Figure 2]. The age range of the study patients was from 2 years to 90 years.
|Figure 1: Distribution of gender and age among the biopsy samples studied.|
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|Figure 2: Prevalence of various categories of glomerulonephritis in the biopsy samples studied.|
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Among biopsies showing primary GN, focal and segmental glomerulosclerosis (FSGS) was the most common lesion seen in 27.6% of the biopsies, (M:F 3:1, mean age 33 ± 16 years) followed by minimal change disease (MCD) seen in 17.7% of the biopsies, (M:F 3:1, mean age 20 ± 11 years) membrano-proliferative GN (MPGN) seen in 13% of the biopsies, (M:F 3:1, mean age 41 ± 21 years) mesangio-proliferative GN (MsPGN) seen in 12.6%of the biopsies, (M:F 1:1, mean age 40 ± 21 years) IgA nephropathy (IgAN) seen in 11.5% of the biopsies (M:F 6:1, mean age 26 ± 16 years) and membranous GN (MGN) seen in 9.9% of the biopsies (M:F 1:1, mean age 40 ± 14 years), as illustrated in [Table 2].
|Table 2: Frequency of primary glomerulonephritis in the renal biopsies studied (n = 348).|
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Among biopsies showing secondary GN, lupus nephritis (LN) was most common, seen in 54.5% of the biopsies, (M:F 1:7 mean age 33 ± 13 years) followed by hypertensive (HTN) nephropathy seen in 22% of the biopsies, (M:F 18:1, mean age 54 ± 14 years) post-infective GN seen in 7.5% of the biopsies, (M:F 2: 1, mean age 27 ± 21 years) diabetic nephropathy (DN) seen in 6.8% biopsies (M:F 2:1, mean age 62 ± 9 years) and vasculitis seen in 4.5% of the biopsies, (M:F 1:5, mean age 48 ± 16 years) as illustrated in [Table 3].
|Table 3: Frequency of secondary glomerulonephritis in the renal biopsies studied (n = 348).|
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In our study, we encountered 14 cases of crescentic GN, six cases each of post-streptococcal GN and vaculitis, three cases each of thin basement membrane disease (TBMD) and IgM nephropathy (all children), two cases each of finger print deposit disease and congenital nephrotic syndrome and one case each of glomerulo-cystic disease and fibrillary GN. Surprisingly, we did not see a single case of Henoch-Schonlein purpura, amyloidosis, Alport's syndrome, human immunodeficiency virus nephropathy or anti-glomerular basement membrane (GBM) disease.
[Table 2] and [Table 3], respectively, show the pattern of primary and secondary GN with respect to frequency, age, gender and child to adult ratio. [Table 4] compares the findings of the current study with some other studies conducted in Saudi Arabia.
|Table 4: Prevalence of glomerular diseases in different studies conducted in Saudi Arabia.|
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| Discussion|| |
In the current study, FSGS was the most common primary GN seen. This result is compatible with the majority of other studies performed in Saudi Arabia, except those of Al-Homrani, Jalalah and Bernieh et al ,,,,,, [Table 4]. Literature from the Western countries  states that FSGS is slightly more common in males, but in our study males dominated by a ratio of 3:1 over females. Unfortunately, we have no data about ethnicity.
MCD was second most common cause of primary GN (17.7%) in our study, while other studies have reported a wide range from 5.4% to 29%, as shown in [Table 4]. MPGN (13%) constituted the third most common cause of primary GN, while other studies again reported a wide range from 2% by Mousa et al  to 38.7% by Al-Homrani et al.  MsPGN was fourth in frequency in our study (12.6%), but Al Homrani from the South found a low prevalence of 4.5% while Musa and Mitwalli  from the Central region reported a higher prevalence ranging between 20% and 25%. IgAN, with 11.5%, came fifth in the current study, while Bernieh et al  did not find a single case (range 0 - 18.9%, [Table 4]. Membranous GN represented 9.9% of primary GN in our study. Jalalah  has reported the highest frequency of MGN in Saudi Arabia of 25.7% in the Western region (range 3.5 - 25.7%, [Table 4].
When we looked into gender distribution and compared the same with the Western population, ,,,, we found a grossly different trend. The Western literature states that MPGN and MCD are equally distributed, while we found a male predominance in both by a ratio of 3:1. IgAN demonstrated a male preponderance by 6:1. For MGN also, we found a difference from the West that has reported a M:F ratio of 2:1, while we found a ratio of 1:1. Our findings also differ from the findings of Jalalah  in the Western region.
We are unable to explain why so much variation exists in the pattern of primary GN in different regions of Saudi Arabia and even in the same region at different centers and at different times [Table 4] as well as other Arab countries. ,,,, We do not know if this is a true pattern shift, a referral bias, different socio economic status, ethnicity or geographical distribution. The answer will be available by maintaining a renal biopsy registry at the national level involving all the centers performing renal biopsies. It should also be ensured that all biopsies include data on the indications, results, ethnicity, nationality, age, gender and geographical locations.
Another question that needs to be answered is why such a major gender difference exists between our study population and the Western counterparts as well as the people in the Western region of Saudi Arabia  in the prevalence of MPGN, MCD, IgAN and MGN. Is it a true trend or just an incidental finding? Again, a renal biopsy registry may provide an answer.
Concerning secondary GN, most studies have shown that LN is the most common cause; our study showed similar results. Hypertensive nephropathy was the second most common cause of secondary nephropathies. Surprisingly, the prevalence of DN in our study was only 6.8%. The most likely reason for this low prevalence is that diabetic patients are not biopsied unless the diagnosis is doubtful.
We came across 14 cases of crescentic GN; vasculitis in five, post-infective in two, LN, IgAN, MsPGN and diffuse proliferative in one case each and not specified in three cases.
Children (aged less than 15 years) constituted 13% of the total biopsies. We found that MCD was the most common GN, followed by FSGS and IgAN. There were three cases of IgM nephropathy in this age group.
We conclude that the pattern of GN seems to vary in different regions of Saudi Arabia. Even different studies performed at different time periods from the same region have reported different patterns. Hence, maintaining a Saudi renal biopsy registry is the need of the hour to get an accurate understanding of the true pattern of GN in the Saudi population. Additionally, we suggest that every hospital should maintain its own renal biopsy registry as well. Further, a better co-ordinated system between primary-care physicians and nephrologists is needed to identify at-risk patients at the earliest to minimize the frequency of patients requiring emergency dialysis.
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Department of Nephrology, Armed Forces Hospital, Riyadh
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]