Deaths resulting from cardiovascular diseases (CVDs) are considered a significant issue among patients with end-stage kidney disease (ESKD) [1]. Patients with ESKD experience cerebrovascular disease mortality rates that are 20 times greater than those in the general population. Additionally, data from a U.S. database of individuals with kidney failure revealed that cardiovascular diseases account for roughly 39% of deaths among dialysis patients [1, 2]. Left ventricular hypertrophy (LVH), which is not uncommon in patients with chronic kidney disease (CKD), is noted as one of the risk factors for cardiovascular disease and death [2]. Along with LVH, there are also changes in cardiac structure and function, which are shown to be prognostic factors in ESKD patients receiving hemodialysis (HD) treatment [3]. Cardiac abnormalities in these patients may develop secondary to multiple factors, including chronic volume and pressure overload, anemia, uremia, high-flow arteriovenous shunts, abnormal calcium and phosphate metabolism, and hyperparathyroidism [4].

LVH is the most common cardiovascular abnormality in patients with CKD [5]. The prevalence of LVH in non-dialysis-dependent CKD patients is around 47%. In comparison, the prevalence of LVH among patients treated with HD or continuous ambulatory peritoneal dialysis (CAPD) is reported to be approximately 75% [6]. When patients who developed LVH were examined, continuing dialysis treatment or the type of dialysis continued did not cause LVH to regress significantly [7].

Although adverse effects of chronic dialysis treatments on left ventricular geometry had be shown, the results of short- and multiple-year cross-sectional studies comparing HD and CAPD treatments on the left ventricle functions were controversial [8]. Hence, we sought to compare the association of dialysis treatment on left ventricular systolic and diastolic functions and left ventricular geometry in HD and CAPD patients.

A total of 47 patients who had been receiving dialysis treatment for an extended period were included in this study. In total, 23 of these patients received HD, and 24 received CAPD treatment. The characteristics of the HD and CAPD patient groups were compared. The mean age of the patients was 58.6 $\pm$ 11.2 years, and the mean dialysis time was 125.1 $\pm$ 35.2 months. A total of 36 (76.6%) patients were observed to have LVH, and 22 (46.8%) were observed to have diastolic dysfunction.

Table 1 compares HD and CAPD patient groups regarding baseline characteristics and dialysis parameters. When the baseline characteristics of patients receiving HD and CAPD were examined, it was found that the average age (p: 0.016) and BMI (p: 0.038) were significantly higher in the group receiving CAPD treatment. No significant difference was found between the groups when the patient’s comorbidities and the underlying primary cause of renal failure were considered. When the medication use of the patients was examined, it was observed that paricalcitol use was significantly higher in the HD group (p: 0.050). No significant difference was observed between the use of other drugs. When patients were evaluated according to dialysis parameters, residual urine was significantly higher in the group receiving CAPD (p: 0.049). Additionally, the calculated Kt/V ratio was significantly higher in the CAPD group (1.92 $\pm$ 0.39 vs. 1.63 $\pm$ 0.26, p: 0.005).

Table 2 compares the CAPD and HD patient groups according to laboratory parameters. Albumin value was significantly lower in the CAPD group (33.9 $\pm$ 5.58 g/L vs. 39.8 $\pm$ 5.31 g/L, p 0.001). Additionally, platelet (p: 0.018), calcium (p: 0.036), and low-density lipoprotein (LDL) cholesterol values (p: 0.005) were found to be significantly higher in the CAPD group. The glucose value was significantly lower in the CAPD group (p: 0.038). Regarding other laboratory parameters, no significant difference was detected between the two groups.

Table 3 compares the CAPD and HD treatment groups according to echocardiographic parameters. When 2D echocardiographic parameters were examined, it was observed that LV mass value (260.7 $\pm$ 64 vs. 224 $\pm$ 59, p: 0.047) and LVMI value (153.3 $\pm$ 34 vs. 130.8 $\pm$ 38.5, p: 0.040) were significantly higher in the group receiving CAPD treatment. There was no notable difference between other 2D echocardiographic parameters. When tissue Doppler parameters were examined, the E/e’ ratio was calculated to be significantly higher in the CAPD group (p: 0.049). When GLS values were analyzed, the GLS values were significantly better in the group receiving HD treatment (p: 0.033). The patients were divided into four groups in terms of LVH (normal, mild, moderate, and severe). The number of patients with severe LVH was significantly more prevalent in the group receiving CAPD treatment (p: 0.002). Concentric hypertrophy was also significantly higher in the CAPD treatment group (p: 0.025). The echocardiogram of the patients with concentric hypertrophy under CAPD treatment is shown in Fig. 2.

The patients were categorized into two groups: those with diastolic dysfunction (22 patients) and those without (25 patients); the parameters that influenced diastolic dysfunction were evaluated. When the effects of age and BMI on the presence of diastolic dysfunction were assessed using univariate regression analysis, no significant effect was found (OR = 1.01, 95% CI: 0.96–1.07; p: 0.59 and OR = 1.04, 95% CI: 0.86–1.27 p: 0.67, respectively). Multivariate analysis showed that receiving CAPD treatment (OR = 90.48, 95% CI: 3.75–2180.57; p: 0.006), history of dyslipidemia (OR = 0.01, 95% CI: 0–0.33; p: 0.008), worse GLS (OR = 16.06, 95% CI: 1.30–198.64; p: 0.031), and calcium value (OR = 7.77, 95% CI: 1.37–44.12; p: 0.021) were independently associated with diastolic dysfunction.

In the average 6-month follow-up of the patient groups receiving CAPD and HD, no statistically significant difference was observed in the number of hospitalizations for various reasons (p: 0.341). During this follow-up period, seven patients in the CAPD group and five patients in the HD group died for multiple reasons, with no significant difference found in the number of deaths (p: 0.740).

The results of this study demonstrated that LV diastolic dysfunction and deteriorations in left ventricular geometry were significantly higher in patients receiving long-term CAPD treatment than in patients receiving long-term HD treatment. CAPD treatment has advantages over HD, such as preserving residual kidney function, providing hemodynamic stability, and improving quality of life. To our knowledge, this is the first study in the literature to compare the association between left ventricular functions in patients undergoing long-term CAPD and HD treatments.

Although previous studies have described the development of LVH and diastolic dysfunction in patients with CKD and receiving HD treatment, this study examined the effects of HD and CAPD treatments on the development of LVH and diastolic dysfunction [8, 21]. The rate of diastolic dysfunction in the CAPD treatment group was significantly higher than in the HD treatment group (66.7% vs. 26.1%, p: 0.005). Additionally, the incidence of LVH was significantly higher in the CAPD treatment group compared to the HD treatment group (91.7% vs. 60.9%, p: 0.002). Based on these results, we can assert that cardiac dysfunctions, particularly LVH and diastolic dysfunction, occur significantly in patients undergoing long-term CAPD treatment.

LVH was present in 76.6% of the patients in our study. This rate was compatible with previous studies in the literature, which observed that the rate of LVH in CKD patients is between 70% and 85% [6, 22]. In our study, the rate of LVH was found to be high (91.7%), especially in the group receiving CAPD treatment. Subsequently, the analysis of previous study on this subject indicates that the incidence of LVH in patients receiving CAPD was approximately 75% [23]. This difference in LVH rate is because the average age of the patients included in this study was higher than that in other studies; moreover, the patients in this study had been receiving CAPD treatment for an extended period. Echocardiographically calculated LVMI values in the patient group receiving CAPD were significantly higher than in the HD group (p: 0.040). We can associate this result with the higher rate of LVH in the patient group receiving CAPD in our study. In the patient population in our study, the E/e’ ratio, one of the diastolic filling parameters, was found to be significantly higher in the CAPD group than in the HD group (p: 0.049). Consistent with our observation, another study found a higher E/e’ ratio in the CAPD group than in the HD group. However, the frequency of diastolic dysfunction was not specified in this cohort [24]. The GLS values of both groups in our study were below normal levels; the literature defines normal GLS values as $>$–18 [25]. The observed GLS values below this in our study can result from patients having CKD for a long time since previous data have shown that GLS decreases significantly in CKD patients [26]. When the between-group differences were compared in our patient population, the GLS values were significantly lower in the patients receiving CAPD treatment (–15.5 vs. –17.5, p: 0.033). We can attribute this result to the fact that the CAPD patients in our study had a higher rate of diastolic dysfunction and LVH count. When the relationship between GLS and mortality in CKD patients was previously examined in the literature, it was found that cardiac events and mortality were higher in patients with low GLS values [27]. Although it would be premature to formulate any conclusion due to the small number of patients in our study, we think future studies should investigate the effect of GLS on mortality in CAPD patients. When the drug use of the patients in our study was examined, it was found that paricalcitol use was higher in the HD group. We think this is because a previous study showed that, paricalcitol treatment, a vitamin D analog can treat hypercalcemia and hyperphosphatemia in patients receiving HD [28]. Interestingly, no prior studies have been conducted on this subject regarding CAPD patients.

When the dialysis parameters of the patients included in our study were examined, the number of patients with residual urine was significantly higher in the patient group receiving CAPD (p: 0.049). Recently it was shown that CAPD treatment protects residual renal functions better than HD treatment. Research has indicated that the residual urine volume in patients undergoing CAPD treatment is greater than in those receiving HD treatment [29]. The data we obtained in our study were observed to be compatible with the data in the literature. When evaluating the Kt/V ratio, one of the methods of measuring dialysis adequacy in the patient population in our study, we observed that this ratio is significantly higher in the CAPD group (1.92 vs. 1.63, p: 0.005). Although there are articles in the literature arguing that this Kt/V ratio used to measure dialysis adequacy should be $>$1.7, the HEMO study, one of the largest studies on this subject, showed that there is no significant difference in mortality and secondary outcomes between cutoff values of 1.7 and 1.3 [30]. With these findings, we showed that dialysis treatments were sufficient in both patient groups in our study, but patients in the CAPD group received more adequate dialysis.

When we examined the laboratory parameters of the patients included in our study, we found that albumin levels in the CAPD group were significantly lower than those in the HD group (p 0.001). This result aligns with previous studies in the literature [31, 32]. Serum albumin is considered a biomarker of visceral protein and a key parameter for nutritional assessment [32]. One reason for the lower serum albumin levels in the CAPD group is thought to be the significantly lower protein intake, as indicated by the Semi-Semi-quantitative Food Frequency Questionnaire (FFQ), along with protein loss through the CAPD fluid [33]. Recently it was suggested that low serum albumin levels are more indicative of persistent inflammation and have limited value as a marker of nutritional status alone [34]. When the biochemical parameters of the patients were examined, it was determined that the calcium value was significantly higher in the patients receiving CAPD treatment, while the glucose value was higher in the patient group receiving HD treatment. However, the patients had no symptoms or findings related to these parameters. These differences in biochemical parameters were claimed to be due to the nutritional habits of the patients rather than the dialysis treatment they receive [35].

When the lipid profiles of our patients were examined, LDL cholesterol levels were significantly higher in the patients receiving CAPD (p: 0.005). High LDL cholesterol levels in the CAPD group were suggested to be due to the glycotoxic effects resulting from the glucose-based solutions used, which may indicate an increased risk of atherosclerosis [36]. Although improved survival rates have been observed in the first 3 years of patients receiving CAPD treatment, the benefits of long-term CAPD treatment remain controversial. Huang et al. [37] demonstrated that LDL cholesterol and apolipoprotein B levels were elevated in peritoneal dialysis patients and concluded that atherosclerosis may be more prevalent in this patient group [38].

The results of this study demonstrated that LV diastolic dysfunction and deteriorations in left ventricular geometry were significantly higher in patients receiving long-term CAPD treatment than in patients receiving long-term HD treatment. Despite adequate dialysis, more cardiovascular pathological changes were detected in patients receiving CAPD than for HD treatment. It would be advantageous to perform additional studies investigating the impact of these cardiovascular changes on prognosis and mortality over extended follow-up periods in larger patient cohorts, including those receiving CAPD treatment.

CVD, cardiovascular disease; ESKD, end-stage kidney disease; LVH, left ventricular hypertrophy; CKD, chronic kidney disease; HD, hemodialysis; CAPD, continuous ambulatory peritoneal dialysis; BMI, body mass index; AVF, arteriovenous fistula; URR, urea reduction ratio; TBW, total body water; TDI, tissue doppler imaging; LA, left atrium; IVSd, end-diastolic interventricular septum; PWd, end-diastolic posterior wall; LVDd, left ventricle end-diastolic diameter; LVDs, left ventricle end-systolic diameter; LVMI, left ventricular mass index; BSA, body surface area; RWT, relative wall thickness; LVEF, left ventricular ejection fraction; LAVI, left atrial volume index; GLS, global longitudinal strain.

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

All authors contributed to the study conception and design. Conceptualization, writing, review, editing and methodology were performed by MU. Resources, material preparation and data collection were performed by ST, NÖŞ, ÖFD and AE. Formal analysis was performed by MCB. The first draft of the manuscript was written by MU and all authors commented on previous versions of the manuscript. All authors contributed to editorial changes in the manuscript. All authors read and approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.

All the procedures in this study including human participants were applied in compliance with the ethical standards of the institutional research committee and the 1964 Helsinki Declaration and subsequent revisions or comparable ethical standards. No animals were used in this study. Patient consent information was received. Approval for the study was granted by the Local Ethics Committee (University of Health Sciences, Bursa City Training and Research Hospital, Clinical Research Ethics Committee, Approval no: 2023-6/12).

Not applicable.

This research received no external funding.

The authors declare no conflict of interest.