Idiopathic nephrotic syndrome (INS) is the most common glomerular disease in childhood worldwide. It is one of the most common causes of childhood renal disease in Africa [1] [2] . It is a podocytopathy resulting in foot process effacement responsible for the triad: edema, massive or nephrotic-range proteinuria and hypoalbuminemia. In 90% of children, there is no cause: this is called idiopathic nephrotic syndrome or nephrosis. In this picture, steroids are used to induce remission and then reduce progression to end-stage renal failure (ESRD) and mortality. The prognosis for childhood INS is best predicted by the patient’s response to initial treatment and the frequency of relapses during the first year after treatment. Unfortunately, it has been widely reported that black children have a poor response to steroids [2] [3] . There is a high incidence of steroid resistance regardless of histopathological pattern in black children in South Africa [4] . Few reports from West Africa and Nigeria have shown steroid sensitivity similar to Asian and European series [5] - [7] .

In the absence of renal disease registries, data on INS are scarce in most sub-Saharan African (SSA) countries [1] . Cameroon, a SSA country located in Central Africa, where public awareness of the renal disease remains limited and treatment costs are not subsidised, has a high burden of chronic kidney disease in children. Chronic glomerulonephritis was the most common aetiology [8] . Fouda et al. previously reported that the incidence of INS was 1.5%, with frequent loss to follow-up within 3 months and a mortality rate of 27% [9] . The aim of our study was to report the early and one-year prognosis of children with idiopathic NS in this setting.

The study received administrative approval from the directors of the participating hospitals and ethical approval from the Ethics Committee of the Faculty of Medicine and Biomedical Sciences of the University of Yaoundé (Institutional Ethics Committee approval n˚ 0437).

During the study period, 215 cases of nephrotic syndrome (34 secondary NS, 50 incomplete files) were recorded, of which 131 INS cases were included.

The aim of our study was to report the prognosis of children with idiopathic nephrotic syndrome from 2018 to 2022 in a cohort of Cameroonian. A total of 131 children were included in this study over a 5-year period. It showed that: 1) Steroid sensitivity was reported in 28.17%; steroid resistance in 64.78%, and steroid dependence in 7.04%. 2) at 8 weeks, remission was obtained in 52.11%. 3) The mortality rate was 12.97%. Survival time averaged 48.2 months, with a crude overall survival rate of 99.2% at 3 and 6 months and 98.4% at 1 year. 4) As for renal survival, renal function was impaired in 8.33% at 6 months and 9% at 12 months.

Keita et al. reported steroid sensitivity in 77% of children aged 02-12 admitted to a nephrology unit in Senegal [11] . This proportion was much higher than in the present study. Indeed, 48.1% of patients presented with hematuria and 30.05% with kidney failure at diagnosis, raising questions about the idiopathic nature of INS in our cohort in the absence of biopsy. Also, Esezobor et al. in Nigeria in 2020 found steroid sensitivity in 85.9% of cases [5] . However, this trend decreased with age, from 92.6% between 0 and 5 years to 69.2% between 11 and 17 years. It must be said that their population was younger than ours (5 years vs. 8 years). This may partially explain our difference. In our series, evolution under steroid treatment was mainly towards steroid resistance. Rural habitats make access to care difficult, and poor adherence to treatment (29. 77% lost to follow-up) and the use of phytotherapy could explain this different response from other series. It is also noteworthy that none of the affected children had a family history of kidney disease, and most were experiencing their first episode (n = 87, 66.4%). This reduces the possibility of potentially steroid resistant familial or genetic NS.

In the Nigerian series by Okoronkwo et al., the trend was towards steroid resistance (69.25%), as in our cohort, with a similar median age at presentation [12] . Asinobi et al. described a similar trend towards steroid resistance [13] . In short, steroid resistance in children varies from 16% - 73.5% [14] . Regarding this great variability, he raised the possibility of misclassification due to variable definitions. In our series INS is treated by adult nephrologists as well as nephropediatricians and there is no local concensus.

Steroid therapy is the treatment of choice for INS. This treatment induces remission in around 90% of cases. However, 70% of these patients relapse and of these, 60% have 5 or more relapses [15] . Patients are said to be steroid dependent if a relapse occurs while steroid doses are being reduced or within 3 months of their cessation. Keita et al. found steroid dependence in 10% of cases in their study in Senegal and 11% were reported in Bamako by Doumbia et al. [11] [16] . This proportion is much higher than in our series (7.04%). Half of all steroid sensitive nephrotic children become steroid dependent or relapse frequently, leading to the need for immunosuppressive drugs (IS). Early prescription of these drugs can reduce disease activity, corticosteroids and their harmful effects [17] .

INS is a morbidity and mortality factor in children [1] . As a result, it poses a real problem due to the complications observed and the lack of follow-up in our setting. At the end of a one-year follow-up, we recorded 17 deaths, representing a mortality rate of 12.97%. These results are higher than those reported elsewhere in Africa, with a pooled mortality of 6.3% [1] . In our context, this could be explained firstly by the delay in consultation, with a delay of between 1 and 6 months (55%), and the use of nephrotoxics (44.3%) conducive to the genesis of added renal lesions. This situation is due to cultural beliefs, insufficient economic resources on the part of parents to cover the cost of treatment, and ignorance.

Glomerular nephropathies are one of the main etiologies of chronic kidney disease (CKD), and are 5 to 6 times more frequent in Africa than in Europe [18] [19] . They are responsible for almost half of all end-stage chronic kidney disease (ESKD) [20] . In our series, 8.33% and 20% of our patients developed chronic kidney failure at 6 months and 12 months. Our results are lower than those of Sabi et al. in Togo, who found that 33.33% of their patients had progressed to CKD, and higher than those of Carter et al. in Canada, who had 1% CKD [21] . This could be explained by the delay in consultation, using nephrotoxic drugs, which further impaired renal function but also by the lack of health insurance.

The mean survival time in our population was 48.2 [40.9 - 55.5] months. The crude survival rate at 3 and 6 months was 99.2% and at one year 98.4%. Our results are similar to those of Olowu et al. in Nigeria in 2010, who found a survival rate of 94.1% at 6 months and 83.7% at 12 months [22] . However, the duration of steroid therapy (p = 0.007), duration of follow-up (p = 0.006) and length of follow-up were factors associated with better survival.

Our results cannot be superimposed on the various African series due to the retrospective design of this study. The large number of patients lost to follow-up reduces the quality of our results. Also, the lack of a consensual case definition, treatment, and follow-up protocol in our setting is a great bias in evaluating the outcome of INS. Renal pathology is not done in Cameroon and must be available for the diagnosis purpose and mainly for treatment guidance.

The pattern of idiopathic nephrotic syndrome is still a concern in our milieu. Many children are lost to follow-up. For those who are treated for the required duration, adherence and the impact of alternative therapies should be investigated to understand the high occurrence of steroids resistance. Free asses to steroids may be able to improve adherence and therapeutic response.

The materials described in the manuscript, including all relevant raw data, will be freely available to any scientist wishing to use them for non-commercial purposes. The data that support the findings of this study are then available from the corresponding author.