Background
Rehospitalization is a major problem for end stage renal disease (ESRD) populations [1–3]. According to the 2018 United States Renal Data System (USRDS) report, about 35.4% of ESRD patients have an unplanned rehospitalization within 30 days after discharge [
1]. Also, rehospitalizations are associated with increased morbidity and mortality and reduced quality of life among dialysis patients [
1‐
3]. Furthermore, inpatient treatment poses a significant financial burden for Medicare expenditures and patients. In 2016, nearly 12 billion dollars had been paid for inpatient care of ESRD patients, accounting for approximately 33% of the total Medicare expenditures for them [
1].
Peritoneal dialysis (PD) is a commonly used method of renal replacement therapy for ESRD patients. The readmission rates of PD patients were quite high, 15.5–37.4%, as reported in developed countries [
1,
4,
5]. Although several studies have investigated the risk factors and prevention strategies of readmission among hemodialysis (HD) patients [
6‐
9], evidence regarding the prevalence and modifiable risk factors of 30-day readmission among PD patients in developing countries was still limited. In addition, the association of rehospitalization and long-term outcomes among these patients had rarely been described.
In this study, we aimed to investigate the prevalence, causes and risk factors of 30-day unexpected rehospitalization among incident PD patients as well as the association between the rehospitalization and long-term outcomes.
Discussion
In the present study, we found that the prevalence of 30-day unexpected rehospitalization in incident PD patients was 9.1% in our PD centre. The top three causes for the rehospitalization were PD-related peritonitis, catheter malfunction and severe fluid overload. Length of index hospital stay and hyponatremia were independently associated with 30-day unexpected rehospitalization. Furthermore, 30-day unexpected rehospitalization increased the risk of all-cause mortality and CVD mortality for incident PD patients.
Previous studies reported that rehospitalization rates were 15.8–37.5% in HD patients [
1,
4,
6,
7,
9] and 15.5–37.4% in PD patients [
1,
4,
5]. Compared to previous studies, the prevalence of 30-day unexpected rehospitalization in our study was much lower. One of the probable explanations might be that patients in our cohort were much younger than those in previous studies. In our study, the mean age was 46.9 ± 15.3 years old, while in the aforementioned studies, the mean age range was 57–66 years old. Older age was a risk factor for morbidity and mortality in the incident dialysis patients [
21], and was also found to be an independent risk factor for unexpected rehospitalization for PD patients [
5]. Secondly, the comorbid status of DM in our cohort was much less than that in the other studies. The proportion of diabetes in our patients was 25.6%, while in Li Z’s study, the proportion was 42.1% [
5]. And in Ziv Harel’s study, the proportion of patients with DM was as high as 62.0% [
7]. DM is strongly associated with macro- and microvascular complications, including CVD, retinopathy, nephropathy, and neuropathy [
22]. These complications might increase the risk of readmission. Thirdly, patients in our study were incident patients, while most of the previous studies included prevalent patients who had pretty long dialysis periods with more comorbidities and worse status [
1‐
4,
6,
7,
9]. Moreover, the specific follow-up management strategies of our centre might also be attributable to the lower rate of unexpected rehospitalization [
23‐
25]. In our center, patients were followed up 3 times within 1 month after discharged. The first follow-up was done by phone within 3 days to make sure that patients were familiar with PD operation and took medications as directed. The second follow-up was done by phone within 2 weeks to evaluate whether their dialysis prescriptions were appropriate, especially whether there was fluid overload. The third follow-up was done within 3–4 weeks by clinical visit to assess the comprehensive health condition after PD initiation. The patients could come back to visit their nephrologist through green channel, and a 24-h on-call service was always provided in the PD center to deal with their emergent problems. Additionally, as most of our patients were living in remote rural areas, we established a PD “satellite center” program across Guangdong Province to provide standardized training for doctors and nurses in satellite hospitals who provided cares to patients in remote areas [
25]. The PD patients who had clinical symptoms in the early stage could be interventedtimely, which would prevent them from deteriorating to the point of admission [
23]. All of the above factors may contribute to the decreased rate of the unexpected rehospitalization in our cohort.
We identified that length of index hospital stay was an independent risk factor of 30-day unexpected rehospitalization. Patients with longer hospital stay always presented with more severe or complicated disease condition during index admission [
26]. Such complex condition not only prolonged their index hospital care, but also made them more vulnerable to an unexpected rehospitalization. Thus post-discharge care plan for these patients should be made carefully. Additionally, we revealed that hyponatremia was another risk factor of rehospitalization. It was reported that hyponatremia was associated with increased risk of 30-day rehospitalization among patients with congestive heart failure [
27]. While in PD patients, hyponatraemia was always accompanied with hypokalaemia [
28], which was a well-recognized risk parameter for peritonitis [
29,
30]. In addition, hyponatremia was reported to be a surrogate marker of longer hospital stay and poorer outcome for PD-related peritonitis [
31]. Also, hyponatremia was reported to be related to a lower level of albumin [
32], which would significantly increase the risk of peritonitis and other infectious diseases [
33]. Moreover, hyponatremia always resulted from inappropriate water gain among PD patients [
32,
34]. Persistent water retention would lead to severe fluid overload or refractory hypertension and finally cause rehospitalization. In addition, it was demonstrated that hyponatremia was strongly correlated with the decline of residual renal function (RRF) [
35], which is a well-recognized risk factor of fluid overload [
17]. In particular, hyponatremia has been found to be significantly associated with an increased risk of infection-related hospitalization and new-onset CVD events for dialysis patients [
36,
37]. All of the above factors increased the risk of rehospitalization for incident PD patients.
It has been reported that rehospitalizations were associated with increased morbidity and mortality and reduced quality of life among dialysis population [
1‐
3]. In the current study, we revealed that 30-day unexpected rehospitalization was independently associated with poor long-term outcomes of incident PD patients. A probable explanation for this finding is that the adverse clinical events that cause early unexpected rehospitalization might also lead to worse prognosis. First, peritonitis was the most common cause of rehospitalization in our study. It is well known that peritonitis could lead to the failure of peritoneal function, resulting in transferring to HD or even death [
16,
38]. Our previous researches demonstrated that early onset peritonitis in incident PD patients affected not only the peritoneal function but also the confidence and compliance of the patients in the treatment modality, which in turn led to worse outcomes [
33]. Second, catheter malfunction was the other important cause of rehospitalization, accounting for 1.8% of our study population, which also was an important cause of early technical failure of PD. Although the prevalence of catheter malfunction was relatively low in our centre, it was still an important cause of 30-day unexpected rehospitalization. Peritonitis and catheter failure were the most common causes of readmission which related to patient education and experience of surgeon. Previous studies by our colleagues have shown that lower education level is associated with the first episode of peritonitis [
29] and long-term all-cause mortality [
39]. We also found that severe fluid overload was another important reason for rehospitalization in this cohort, accounting for 1.2% of our study population. Fluid overload not only played an inverse role in the preservation of RRF [
17,
40] but also increased both all-cause and CVD mortality [
17]. All of these aforementioned events could lead to poor outcomes. The rest of the rehospitalization reasons, such as CVD events, non-peritonitis infection, etc., would also result in a poor prognosis undoubtedly [
3,
20].
Our study has several limitations. First, all of the data were collected from a single centre. The results may not be generalizable to other centres. Second, we were not able to consider all variables potentially associated with the rehospitalization and long-term outcomes. Further studies that take into account more risk factors, such as post-discharge medical care, health literacy and social support, are warranted. Nonetheless, to our knowledge, this was the first study concerning 30-day unexpected rehospitalization in a large cohort of incident PD patients in developing country. The strengths of our study included its large cohort and complete follow-up data. The results of our study might be of value in guiding clinical practice.
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.