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In CKD, sex (biological) and/or gender (sociocultural) differences in both the pathogenesis of the disease and the response to treatment are increasingly pronounced. In Uruguay, data from the National Renal Healthcare Program (NRHP-UY) have shown that in 14,659 patients, 56.9% were male (M). According to data from the Uruguayan Dialysis Registry (UDR), chronic dialysis (CD) incidence was 215 pmp with a higher rate in male (M) vs female (F) (273 vs 161 pmp) in 2022. It has been proposed that, in developing countries, the lower prevalence of F in CD would be linked to a lower inclusion of women in the formal work sector with the consequent difficulty of access to the health system. Since CKD treatment coverage in Uruguay is universal, there should be no difficulties in the F access, which provides an ideal scenario to analyze the differences in dialysis admission independently of treatment accessibility. The aim of this work is to analyze sex as a determinant of the speed of progression and access to different treatment options, in a cohort of patients in CD in Uruguay
A descriptive, analytical, and retrospective study of CD patients between 2005 and 2020 was performed. The follow-up period began at the start of nephrological control on admission to the NRHP-UY (for those included in it) or at the start of CD (for those not included in the NRHP-UY) and ended on 31/12/2020 or at the time of discharge due to renal transplantation (RT) or death. The data were provided by the UDR and the NRHP-UY. The chi-square test was used for the analysis of qualitative variables and the t-test or non-parametric test was used for quantitative variables, depending on the distribution. Survival was estimated by the Kaplan-Meier formula and the Cox proportional hazard model was used to evaluate the risk of death (HR), adjusted for confounding variables, with a value of p<0.05 being considered significant.
We analyzed 10,117 patients (61.0% M sex) with a median follow-up of 43 months (IQR 17.81). Only 3,084 patients (30.5% of the total) were included in the NRHP-UY. The median time between the start of nephrological controls and the start of CD was 29 months (IQR 11.63) for F and 30 months (IQR 11.63) for M (p=NS). The rate of progression of CKD was slower for F than for M (9.6±11.1 vs 10.5±10.9 ml/min/year; p<0.05). When considering all patients, the percentage of patients with unplanned start dialysis was lower in women than in men (68.8% vs 73.2%; p<0.05). F initiated CD at a younger age than M (60.9±17.4 vs 62.4±16.7 years; p<0.05) and with a lower calculated glomerular filtration rate (9.5±5.1 vs 10.7±5.4 ml/min; p<0.05). We found no difference between sexes in the percentage of patients with very limited physical capacity or inability to care for themselves (31.3% F vs 29.9% M; p=NS). Admission to the waiting list for RT among patients younger than 65 years showed no difference (22.8% M and 23.7% F, p=NS). RT was similar for both sexes: 11.0% for F and 11.2% for M. Adjusted DC survival was 51 months for the whole population (57 F, 48 M; p<0.05) (Figure 1), HR for F was 0.87 (p<0.05).
TITLE: Table 1. Characteristics of CKD and treatment according to sex.
Footnote: CKD: chronic kidney disease, IQR: interquartile range, SD: standard deviation. *p≤0.05
We concluded that in Uruguay, F progress slower and start dialysis at earlier ages and more frequently planned than M. Mortality in dialysis is lower, with similar access to RT. With the information analyzed, we did not identify inequities associated with sex in the nephrological care process. The analysis of the natural history of CKD in Uruguay offers a good model for the study of inequities in health care