|Year : 2020 | Volume
| Issue : 2 | Page : 176-182
Recurrence of nephrolithiasis: incidence and risk factors in Egyptian patients
Mostafa M Ebraheem1, Alsayed S Abdelaziz2, Ayman M Ghoneem3, Esam A Elnady4
1 Department of Urology, Ahmed Maher Teaching Hospital, Cairo, Egypt; Department of Urology, Ibn Sina College Hospital, Jeddah, Kingdom of Saudi Arabia
2 Department of Urology, Faculty of Medicine, Al-Azhar University, Damietta, Egypt; Department of Urology, Ibn Sina College Hospital, Jeddah, Kingdom of Saudi Arabia
3 Department of Urology, Faculty of Medicine, Tanta University, Tanta, Egypt; Department of Urology, Ibn Sina College Hospital, Jeddah, Kingdom of Saudi Arabia
4 Department of Urology, Faculty of Medicine, Al-Azhar University, Damietta, Egypt
|Date of Submission||09-Jan-2020|
|Date of Decision||11-Mar-2020|
|Date of Acceptance||19-Apr-2020|
|Date of Web Publication||24-Jul-2020|
MD Mostafa M Ebraheem
Department of Urology, Ahmed Maher Teaching Hospital, Cairo, 11865, Egypt
Source of Support: None, Conflict of Interest: None
Introduction Recurrence of nephrolithiasis is common. The knowledge of its incidence and risk factors is the base for proper prophylaxis and preservation of renal function.
Objective The aim was To study the recurrence rate and risk factors of nephrolithiasis in Egyptian patients.
Patients and methods Files of 974 patients with nephrolithiasis (634 males and 340 females, aged 7–70 years) were reviewed. They were managed between 2008 and 2009, with a 10-year follow-up period since the first stone episode for recurrence. Stone characteristics (sizes, sites, and multiplicity), treatment type, post-treatment residual stones, family history, BMI, and recurrence rate were included.
Results Of the 974 patients, stone recurrence rate was 44.45% within 10 years of follow-up. Recurrence was significantly higher in young age group of less than 20 years, male sex, average BMI, and positive family history (61.14, 52.99, 50.99, and 55.82%, respectively) within 10 years. Recurrence was significantly higher with stone size greater than 2 cm (24.20%) at the second 5-year follow-up. Recurrence was significantly higher with multiple (56.59%), pelvicalyceal (59.83%), and bilateral (66.95%) renal stones within 10 years. It was significantly higher with shock wave lithotripsy (20.89%) within the second 5-year follow-up, and with presence of residual stones (32.66%) within the first 5-year follow-up.
Conclusion Stone recurrence rate increases with increase in observation time. Risk factors for recurrence are young age of onset; male sex; normal BMI; positive family history; large size, multiple, bilateral, and pelvicalyceal stone; shock wave lithotripsy treatment; and presence of residual stones.
Keywords: nephrolithiasis, recurrence, risk factors
|How to cite this article:|
Ebraheem MM, Abdelaziz AS, Ghoneem AM, Elnady EA. Recurrence of nephrolithiasis: incidence and risk factors in Egyptian patients. Al-Azhar Assiut Med J 2020;18:176-82
|How to cite this URL:|
Ebraheem MM, Abdelaziz AS, Ghoneem AM, Elnady EA. Recurrence of nephrolithiasis: incidence and risk factors in Egyptian patients. Al-Azhar Assiut Med J [serial online] 2020 [cited 2020 Aug 9];18:176-82. Available from: http://www.azmj.eg.net/text.asp?2020/18/2/176/290603
| Introduction|| |
Urolithiasis is the third most common affliction of the urinary tract. Definite etiology of stone formation and recurrence is unknown . Approximately 50% of patients with renal calculi have a recurrence within 10 years ,. Metabolic evaluation is a poor predictor for the risk of recurrence .
Risk factors of renal function affection are number of stone recurrence, stone size, attacks of urinary tract infection with obstruction, and urological interventions . The knowledge of the risk factors of stone recurrence is the base for proper prophylaxis . Prevention of stone recurrence, proper management of already formed stones, and eradication of infection will improve renal function .
| Aim|| |
The objective of this study was to evaluate the rate of recurrence of nephrolithiasis and its risk factors in Egyptian patients in relation to patient and stone characteristics and modalities of treatment and its results.
| Patients and methods|| |
After receiving Local Institutional Review Board Approval, this retrospective study was performed from June 2018 to October 2019. This study was retrospectively conducted in a cohort of Egyptian patients who were complaining of renal stone disease. Medical records of 1316 had been reviewed. Only 992 patients met the inclusion criteria to be enrolled in this study. From this, only 974 patients had complete file data ([Figure 1]). Sometimes we contacted patients to obtain some missed data. Of the 974 patients, 634 were males and 340 were females, aged from 7 to 70 years, with a mean of 38.8±13.7 years, who were managed for the first stone episode between 2008 and 2009, with a 10-year follow-up period since the first stone episode.
Data were collected by nonrandom convenience sampling, and we selected patients based on their availability for the study. All files with incomplete data, untreated patients, patients treated by nephrectomy, patients on stone prophylactic measure, and patients with follow-up duration less than 10 years were excluded.
During collection of the data, we considered the following: date of onset, duration of follow-up, sex, age of onset, family history, BMI, stone characteristics (site, size, and multiplicity), type of primary stone management, presence of residual stones after treatment, and episodes of recurrence.
Data management and analysis were performed using statistical analysis systems, SAS VS 8.02 (SAS Campus Drive Cary, North Carolina, USA). Numerical data were summarized using means and SD or medians and ranges. Categorical data were summarized as percentages. χ2-test was used to compare groups with respect to categorical data. Recurrence rate was measured within 10 years after the date of primary treatment. P values less than 0.05 were considered significant.
| Results|| |
Of the 974 patients, the rate of first stone recurrence was 24.94 and 17.96% within first and second 5-year follow-up, respectively. However, the second recurrence rate was 1.54% within 10 years of follow-up. Overall recurrence rate was 44.45% within 10 years of follow-up ([Table 1]).
Young age of onset had significant higher rate of recurrence. In the age group less than 20 years, the rate of first stone recurrence was 33.8 and 19.71% within first and second 5 years of follow-up, respectively. Second recurrence was 5.63% within 10 years of follow-up. Overall recurrence was 61.14% within 10 years of follow-up ([Table 2]). Moreover, males had significant higher rate of recurrence. The rate of first stone recurrence in males was 29.81 and 21.45% within first and second 5 years of follow-up, respectively. Second recurrence was 1.73% within 10 years of follow-up. Overall recurrence was 52.99% within 10 years of follow-up ([Table 3]).
Normal BMI had significant higher rate of recurrence. The rate of first stone recurrence was 27.41 and 21.97% within first and second 5 years of follow-up, respectively. Second recurrence was 1.61% within 10 years of follow-up. Overall recurrence was 50.99% within 10 years of follow-up ([Table 4]). Moreover, patients with positive family history of nephrolithiasis had significant higher rate of recurrence. The rate of first stone recurrence was 30.13 and 23.45% within first and second 5 years of follow-up, respectively. Second recurrence was 1.88% within 10 years of follow-up. Overall recurrence was 55.82% within 10 years of follow-up ([Table 5]).
The rate of first stone recurrence was significantly increased with large stone size (>2 cm). It was 24.20% within second 5 years of follow-up. Second recurrence was 2.0% within 10 years of follow-up ([Table 6]). Moreover, multiple renal stones had significant higher rate of recurrence. The rate of first stone recurrence was 29.08 and 25.18% within first and second 5 years of follow-up, respectively. Second recurrence was 2.33% within 10 years of follow-up. Overall recurrence was 56.59% within 10 years of follow-up ([Table 7]). Moreover, patients with pelvicalyceal stones including stag horn stones had significant higher rate of recurrence. The rate of first stone recurrence was 30.05 and 27.97% within the first 5 and second 5 years of follow-up, respectively. Second recurrence was 1.81% within 10 years of follow-up. Overall recurrence was 59.83% within 10 years of follow-up ([Table 8]). Moreover, patients with bilateral renal stones at the time of diagnosis had significant higher rate of recurrence; the rate of first stone recurrence was 35.71 and 29.46% within first and second 5 years of follow-up, respectively. Second recurrence was 1.78% within 10 years of follow-up. Overall recurrence was 66.95% within 10 years of follow-up ([Table 9]).
|Table 6 Stone recurrence in related to size of the stones of the patients|
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|Table 7 Stone recurrence in related to multiplicity of the stones of the patients|
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|Table 8 Stone recurrence in related to locations of the stones of the patients|
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|Table 9 Stone recurrence in related to laterality of the stones of the patients|
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First stone recurrence rate was significantly increased with shock wave lithotripsy (SWL) than percutaneous nephrolithotomy and open lithotomy only within the second 5 years of follow-up (20.89, 10.62, and 15.68 for SWL, percutaneous nephrolithotomy, and open lithotomy, respectively) ([Table 10]). Regarding stone clearance, the first stone recurrence rate was significantly higher with the presence of residual stones within the first 5 years of follow-up only. It was 32.66% of patients. However, second recurrence was insignificant between both groups ([Table 11]).
|Table 10 Stone recurrence in related to treatment modalities of the stones|
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|Table 11 Stone recurrence in related to post-treatment clearance of stones of the patients|
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| Discussion|| |
After management of renal calculi, patients should be stratified into low-risk or high-risk groups of stone recurrence. For perfect group distribution, stone analysis and basic assessment for every single patient for risk factors are essential. Low-risk group of stone recurrence will significantly benefit from general prophylactic measures regarding fluid and diet intake plus lifestyle modification, whereas in the high-risk group, specific measures are needed for proper metabolic assessment and individualization of treatment protocol to minimize or prevent recurrence .
In our study, nephrolithiasis is more common in men (65.1%) than in women (34.9%) (ratio1.8 : 1) and is more prevalent between the ages of 20 and 50 years. These findings were similar to the findings of the epidemiological studies, which revealed that nephrolithiasis is more common in men (62.3%) than in women (37.7%) and is more prevalent between the ages of 20 and 40 in both sexes ,. Initial presentation predominates in the third and fourth decade . Moreover, some of the studies reported that in developing countries, the male-to-female ratio ranged from 1.15 : 1 in Iran, to 1.6 : 1 in Thailand, to 2.5 : 1 in Iraq, to 5 : 1 in Saudi Arabia .
Assessment of risk of recurrence of nephrolithiasis is a common part of the medical care of patients with all types of stone disease. The incidence of urinary stones has been increasing recently with a prevalence of greater than 10% and an expected recurrence rate of nearly 50%. Stone disease has an important effect on the health care system ,.
In this series, recurrence rate increases with increase in observation time, and first stone recurrence occurred in 24.94 and 17.96% of the patients within first 5 and second 5 years after the first stone episode, respectively. Second recurrence occurred in 1.54% within 10 years of follow-up. Overall recurrence rate was 44.45% within 10 years of follow-up These findings were near to the findings of others, who found that up to 50% of patients with previous urinary calculi have a recurrence within 10 years ,. Moreover, our findings were almost similar to the findings of the study of the natural history of renal stone recurrence, which concluded that 53% of the patients developed recurrences during 8 years following the first attack, the risk of which was highest during the first years after the initial attack .
Moreover, these findings are comparable to the findings of Strohmaiel, who found that the average recurrence rate is 30–40%. Recurrence rate increases with increase of age and prolongation of observation time. Moreover, Leusmann reported that the recurrence rate is about 50% within 5–10 years and 75% within 20 years and more than 50% of all recurrent stone formers have only one recurrence during their lives, and 10% of recurrent stone formers have more than 3 recurrences . Following an initial stone event, the 5-year recurrence rate in absence of specific treatment is 35–50% .
These findings support the findings of Strohmaiel  who reported that risk factors for recurrence are male sex, multiple and lower calyx stones, early onset, familial history, and complications after stone removal. Moreover, our findings are similar to the findings of Sun and his colleges and Di Silverio and his colleges who reported that male sex and history of multiple renal stones are risk factors for relapses after SWL. Most investigators accept that SWL increases the risk for late stone relapses because this depends on the existence of so-called clinically insignificant residual fragments ,.
The EAU guidelines give high recommendation for general preventive measures that should be applied to all stone former in all risk groups. These measures including good fluid intake, changing bad nutritional habits, and lifestyle modification. High-risk group of stone recurrence needs specific prophylactic measures, usually pharmacological depending on stone analysis .
Regardless of the stone prophylaxis measures, it is unclear whether dietary management alone, pharmacologic management alone, or combined dietary and pharmacologic management is the best for stone prophylaxis. Many research studies assigned men with recurrent renal stone and soft drink consumption to reduced soft drink intake or no treatment. Although the intervention significantly reduced the risk for symptomatic recurrent stones, the level of evidence for this outcome is low because results were from only one insufficient trial ,. The benefit of long-term prophylaxis with good patient compliance not exceeding 70–80% and with the first attack of stone disease, medical therapy may not be of valuable cost-benefit for all patients .Patients in high-risk group of stone recurrence should be more precisely followed with radiological assessment. A symptomatic renal stone should be annually imaged till showing lack of disease progression. Minimizing radiation exposure with any radiological follow-up protocol is essential with sound options of renal ultrasound and/or KUB plain radiography .
Renal stone recurrence and/or symptomatizing of silent kidney calculi are motivators to repeat metabolic assessment and avoid any missed abnormality in previous assessment and tailoring preventive plane to minimize recurrence later on ,.
Limitations were as follows: one limitation is that the retrospective aspect of this study may introduce sample bias and/or information bias and may not reflect the general population. The hope is to do a prospective similar research in the future to overcome these limitations. Another limitation is that the limited literature in this area minimized the power to give evidence-based recommendations for imaging follow-up or repeat metabolic assessment in patients with renal stones.
| Conclusion|| |
Stone recurrence rate increases with increase observation time. Risk factors for recurrence are young age onset; male sex; normal BMI; positive family history; large size, multiple, bilateral and pelvicalyceal stone; SWL treatment; and presence of residual stones.
Mostafa M. Ebraheem and Alsayed S. Abdelaziz conceived the presented idea; Ayman M. Ghoneem verified the analytical methods; Alsayed S. Abdelaziz encouraged Esam A. Elnady to investigate and supervise the findings of this work; all authors discussed the results and contributed to the final manuscript; Ayman M. Ghoneem and Esam A. Elnady wrote the manuscript with the support from Alsayed S. Abdelaziz and Mostafa M. Ebraheem, Esam A. Elnady performed the analytic calculations and performed the numerical simulations; both Alsayed S. Abdelaziz and Ayman M. Ghoneem contributed to the final version of the manuscript; Mostafa M. Ebraheem supervised the project; Alsayed S. Abdelaziz, Mostafa M. Ebraheem, and Ayman M. Ghoneem, contributed to the design and implementation of the research, to the analysis of the results, and to the writing of the manuscript; all authors provided critical feedback and helped shape the research, analysis, and manuscript.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11]