Screening for Chronic Kidney Disease in Relatives of Hemodialysis Patients

Objective: To estimate the prevalence and socioeconomic characteristics of Chronic Kidney Disease (CKD) in first and second-degree relatives of patients on hemodialysis Method: A questionnaire was applied on socioeconomic conditions, lifestyle, and personal pathological background. The formula of CKD-EPI and/or proteinuria greater than or equal to 1+ was used to characterize CKD. Analysis using the logistic regression model. Results: 408 individuals were evaluated and 12% had CKD. 6.61% had a glomerular filtration rate (GFR) ≤ 60 mL / min / 1.73 m2 and 5.39% proteinuria in the urine. The variables associated with the presence of CKD were age (OR = 1,60; 95% IC = 1,31-1,96), PAS (OR: 1,69; 95% IC: 1,24-2,28), PAD (OR: 1,52; 95% IC: 1,18-1,96) and blood glucose (OR: 2,03; 95% IC: 1,38-2,99). Conclusion: It is necessary to implement routines for systematic evaluation that prevent or delay the loss of renal function, in addition to measures that improve the pre-dialysis clinical conditions of this population.

The practice of physical activity and smoking were also questioned. Of the participants, 146 (35.78%) reported practicing some physical activity, of which 15 (30.61%) were diagnosed with CKD. 38 (9.31%) individuals reported smoking, of these three (6.12%) had CKD. When the chi-square test was applied, there was an association between CKD and kinship (p <0.001) and age (p <0.001) ( Table 1).
Regarding previous knowledge about CKD and hemodialysis, 280 (68.6%) had no knowledge about CKD, and 214 (52.45%) did not know about hemodialysis. The association of both knowledge of kidney disease and HD with the presence of CKD was tested using the chi-square test, with no significant association (p = 0.65 and p = 0.19, respectively) ( Table 2).
CKD was classified into five stages according to the criteria adopted by K/DOQI (2002). It was found 21 (42.85%) in stage 3A and 10.20% in 3B (Table 5).
After three months, participants with CKD were reassessed, except for eight (16.32%) individuals due to refusal or change of address (city), as shown in Table 6.

DISCUSSION
The prevalence of CKD found in the first phase of this study was comparable to most of those that have already been executed, even with the average age (39 years) lower than those performed using the KEEP profile, such as KEEP Japan, in which the average age was 59.7 years, with age being a well-established risk factor for CKD (Takahashi, Okada & Yanai, 2010;Obrador et al., 2010;Brown et al., 2003). After the reassessment in three months, we had a 38.75% decrease from the initial value. As in the study by Afolabi, Abioye-Kuteyi, Arogundade & Bello (2009) the group diagnosed with CKD by the proteinuria criterion was the one that showed the greatest return to normal parameters. This fact corroborates the need for reassessment of these individuals and questions the real prevalence of CKD, especially in studies that used proteinuria as the only criterion and without reassessment. When compared with studies carried out in Brazil, a higher prevalence was observed, such as that found by Passos et al. (2003). According to our knowledge, only Bastos et al. (2009) reassessed the interviewees after three months, obtaining a smaller decrease in prevalence (from 12.4% to 9.6%). However, a minority of research carried out in Brazil adopts both proteinuria and GFR and a reassessment in three months for the diagnosis of CKD, as carried out in this study.
When individuals were stratified according to the degree of renal dysfunction, values similar to those reported by most international studies were obtained, with a predominance of stage 3, as occurred in the American KEEP study (stage 1: 21%; stage 2: 19%; stage 3: 33% and stage 5: 3%) (Brown et al., 2003) This allows intervening in the natural evolution of the disease and can preserve kidney function if this diagnosis is made early. In Brazil, few studies have stratified participants, among which the one with the largest number of individuals was ELSA-Brasil, finding 1.5% in stage 1, 2.6% in stage 2, 4.0% in stage 3, 0.6% in stage 3b, 0.2% in stage 4 and 0.1% in stage 5 (Barreto et al., 2016). As in the present study, there was no predominance of participants in stage 3 of CKD.
Although there is no justification in the literature, it is observed that there is a higher prevalence of CKD in women (Obrador et al., 2010;Lima, Kesrouani, Gomes, Cruz & Mastroianni-Kirsztajn, 2012), including in the studies conducted by Freedman, Soucie & McClellan (1997) and Wei et al. (2012) who evaluated relatives of patients with kidney disease. In this study, even without obtaining statistical significance between the sexes, it was observed that the majority of participants with CKD were women, especially in more advanced stages, but it was not possible to determine a cause/effect relationship.
Risk factors already established, such as hypertension and diabetes, behaved similarly to worldwide studies, demonstrating that relatives of kidney patients have several associated risk factors. In the NHANES studies 1988-1994 and 1999-2002 and in the KEEP studies Mexico, Japan, and the USA, this association was well established (Takahashi, Okada & Yanai, 2010;Obrador et al., 2010;Brown et al., 2003;NHANES 2013NHANES -2014NHANES , 2013). In the present study, the values found for Systemic Arterial Hypertension (46.93%) and diabetes (26.52%) were similar to those found by Bastos et al. (2009) corroborating its importance for CKD. These pathologies have been associated with CKD. It seems reasonable to think that families that have individuals who have lost kidney function due to these pathologies are more likely to develop CKD.
Other "new" risk factors such as obesity and smoking have been associated with CKD, but it was not possible to establish this association, probably due to the low percentage of obese and smokers in this sample (25.92 and 3.7% respectively) which are in opposition to what was reported in the KEEP USA (44 and 45%, respectively) (Passos et al., 2003). The values in the present study were closer to those reported in a survey conducted in Egypt that also did not observe any association of these factors with CKD (Gouda et al., 2011). On the other hand, the regular practice of physical exercise has also not been shown to have a protective effect on CKD in this sample.
CKD has a worldwide distribution; however, it is important to remember that in countries with an economic profile similar to Brazil, the lower economic and educational classes are the most affected, either due to lack of access to the health or information system (Brown et al., 2003). In the present study, most participants diagnosed with CKD had lower levels of education (63.26%) and social class (75.51%). When asked about the knowledge that this population had about CKD and hemodialysis and there is a high prevalence of non-knowledge about CKD (68.62%) and hemodialysis (52.45%) in the same way as the results found by Khalil and Abdalrahim (2014) in which about half of the study participants had no information about the pathology. Even though it is not possible to demonstrate statistical significance for these variables, it is believed that the greater clarification about CKD, can contribute positively so that a greater number of relatives of chronic renal patients seek to assess their renal health early.

CONCLUSION
It is clear that there is still a long way to go before the real prevalence of CKD is precisely known, especially in Brazil.
The methodology used in this study was based on the use of the criteria established for the correct diagnosis and staging of CKD, accepted internationally, with results similar to those already published in the literature, confirming the need for public health measures aimed at the early diagnosis of CKD in Brazil.
The relatives of patients with CKD are at risk, and unlike hypertensive and diabetic patients who have specific health policies, they go unnoticed even in hemodialysis clinics, where they often take their relatives for dialysis. There are findings of several participants with relevant renal dysfunction, including stage 5, which justifies the implementation of simple routines, especially in hemodialysis clinics, to identify and clinically measure this population early.
CKD is a silent pathology for patients and doctors. It has high costs for the health system and the quality of life of the patient and his family. "Any" gain in time without dialysis justifies the creation of simple routines to identify CKD early.