Based on the findings, it was found that sarcopenia was significantly associated with higher risk of all-cause hospitalization in the 48-week follow-up. In sensitivity analyses, excluding participants lost in the follow-up, the relationships between sarcopenia and hospitalization remained unchanged. According to subgroup analyses, participants in subgroup (male or female; < 60 or ≥ 60 years) diagnosed with sarcopenia were still associated with an increased risk of hospitalization during the 48-week follow-up period. To the best of our knowledge, this is the first longitudinal study to investigate the associations of sarcopenia and hospitalization among Chinese PD patients.
Two studies followed dialysis patients to assess the impact of sarcopenia on hospitalization outcomes. The first study included 126 chronic HD patients with 3-year follow-up. The authors reported no significant difference in the incidence of hospitalization between sarcopenic and non-sarcopenic patients without absolute reported number19. In contrast, the second study followed 170 patients on maintenance HD for 3 years. The risk of hospitalization was significantly higher in sarcopenic patients with a fully adjusted RR (adjusted for age, sex, dialysis vintage, and diabetes mellitus) of 2.07 (95%CI 1.48–2.88)20. In our study, compared to non-sarcopenia group, the cumulative incidence of hospitalization in sarcopenia group was significantly higher (65.5% vs. 34.7%, P < 0.001), with an estimated RR of 1.90 (95%CI 1.43–2.52) in PD patients. The paradoxical results may be partly explained by varied sarcopenia definitions, inconsistent inclusion criteria, and different sample sizes in these studies. Thus, for the hospitalization, more evidence is needed to conclude associations with sarcopenia in dialysis patients. Of note, muscle disuse and bed rest during hospitalization may further increase muscle and strength losses, which may persist even after hospital discharge22,23. This scenario turns CKD patients that have been previously hospitalized more prone to falls, fractures, infections, and rehospitalization24,25.
Our study showed that the most common causes of hospitalization were fatigue (58.0%), which has been increasingly recognized as an important symptom in patients with kidney failure requiring maintenance dialysis26. Fatigue affects 20%-91% of patients with CKD, and the prevalence increases with advancing CKD stages27,28,29. In sum, approximately two-thirds to three-quarters of patients with CKD experience fatigue, with as many as one in four reporting severe symptoms. Sarcopenia is one of the most concerning results of protein-energy wasting and is a strong correlate of poor physical functioning30, which may further aggravate the symptom of fatigue. A previous study evaluated 119 PD patients with the mean age of 66.8 ± 13.2 years and the mean follow-up period of 589.2 days. According to the multivariate logistic regression model, sarcopenia was significantly correlated with frailty (adjusted OR = 12.2, 95% CI 2.27–65.5) 31. Meanwhile, a prospective study of 266 consecutively recruited outpatients with CKD stages 2–5 reported that the presence of any fatigue versus none, were independently associated with a composite of death, hospitalization, or dialysis initiation32.
Cardiovascular disease (CVD) is a highly common cause of hospitalization in patients undergoing dialysis. The relationship between sarcopenia and cardiovascular events were reported in two studies33,34 and were included in a meta-analysis. According to adjusted OR, sarcopenia was significantly associated with increased cardiovascular events in dialysis patients (adjusted OR = 3.80, 95%CI 1.79 to 8.09)3. The meta-analysis demonstrated that sarcopenia in dialysis patients was one of the most important predictors of cardiovascular events, and this was independent of study design, population, sex, continent, dialysis method, sarcopenia definition, and study quality3.
We also explored the association between sarcopenia and hospitalization in the subgroup. Although sarcopenia has been traditionally seen as a condition associated with age, however the subgroup analyses by age (< 60 years and ≥ 60 years) failed to demonstrate a difference in the association between sarcopenia and hospitalization in our study, implicating the importance of screening sarcopenia even in young PD patients. These results may be attributed to the systemic inflammatory condition and multiple comorbidities in dialysis-dependent patients, which could reduce the interaction between age and sarcopenia. Moreover, the analysis suggested that the sex had no significant effect on the correlation of sarcopenia and incidence of hospitalization. Of course, these relationships require verification in studies with large dialysis cohorts.
Some limitations of our study should be taken into account. First, because of the inherent drawbacks of observational studies, a causal relationship cannot be clearly established. Even though we have adjusted as many relevant covariates as possible in the post hoc statistics, there may be still profound residual and unmeasured confounding factors that could not be completely ruled out, which may contribute to a different outcome. Second, the follow-up duration was relatively short, spanning 48 weeks. Consequently, the long-term association between sarcopenia and hospitalization in patients undergoing dialysis could not be monitored. Conversely, dynamic changes in sarcopenia or their parameters with long-term follow-up may provide additional prognostic information. Third, the patients’ previous history of hospitalization, as a potential confounder of rehospitalization, was not deliberately considered before study, and its absence of details could have introduced some degree of bias, potentially weakening the statistical power toward the null hypothesis. Finally, only 220 cases were included in the primary analyses. Owing to relatively small sample size, there may be an increased risk of random error. The confounding factors could not be fully adjusted in regression analyses, leading to an inaccurate estamation of OR and a wider range of 95% CI (Fig. 2).
In conclusion, we demonstrated the associations of sarcopenia with higher risk of hospitalization by longitudinal analysis in PD patients, implicating that it is necessary to highlight the impact of sarcopenia among PD patients and recommend individualized lifestyle intervention that may be implemented across the health care spectrum. Because of the limitations of study, and potential for type I error, the findings should be interpreted as exploratory. More evidence is needed to draw robust conclusions and comfirm the causal relationship of sarcopenia and its traits with hospitalization in dialysis patients.
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- Source: https://www.nature.com/articles/s41598-024-65130-0