Date Published: November 29, 2018
Publisher: Public Library of Science
Author(s): Inayat Ur Rehman, Syed Munib, Amutha Ramadas, Tahir Mehmood Khan, Hugh C Rayner.
The prevalence of chronic kidney disease-associated pruritus (CKD-aP) varies from 22% to 84% among patients receiving hemodialysis. It occurs more frequently at night, and often affects patient’s sleep quality. CKD-aP is often unreported by patients, and many do not receive effective treatment. There is, however, a paucity of available data on the prevalence and impact of CKD-aP on patients receiving hemodialysis in Pakistan.
A multicenter cross-sectional study was undertaken from July 2016 to April 2017 at a tertiary care hospitals in Pakistan.
354 patients undergoing hemodialysis were studied. 35.6% had CKD for 1–2 years, and 42.4% were receiving hemodialysis for 1–2 years. The prevalence of pruritus was 74%. The median [interquartile range] score for pruritus was 10.0 (out of possible 25) [8.0–12.0]; while the median [interquartile range] Pittsburgh Sleep Quality Index (PSQI) score was 8.0 (out of possible 21) [7.0–10.0]’. Pruritus was significantly correlated with the sleep score (r = 0.423, p<0.001). The results of the multivariate linear regression revealed a positive association between pruritus and age of patients (β = 0.031; 95% CI = 0.002–0.061; p = 0.038) and duration of CKD (β = -0.013; 95% CI = -0.023 –-0.003; p = 0.014). Similarly there was a positive association between sleep score and duration of CKD (β = 0.010; 95% CI = 0.002–0.019; p = 0.012) and pruritus (β = 0.143; 95% CI = 0.056–0.230; p = 0.001). Chronic kidney disease-associated pruritus is very common in patients receiving hemodialysis in Pakistan. Pruritus is significantly associated with poor sleep quality.
Pruritus is a troublesome complication which affects the health-related quality of life (HRQOL) of patients with end-stage renal disease (ESRD) . Chronic kidney disease-associated pruritus (CKD-aP) is an undesirable condition that triggers itching, and negatively affects sleep quality . It has been reported that the prevalence of pruritus ranges from 40–70% [3–5], while sleep disorders due to CKD-aP ranges from 28.8–90% [6–10]. CKD-aP has been found to result in nocturnal awakenings and difficulty in falling asleep [4, 11]. Indeed patients on hemodialysis suffering from moderate to extreme pruritus were found to be three times more likely to have poor quality of sleep  In a study done by Yamada et al., pruritus was reported in 66.9% of hemodialysis patients, and of these, 41.2% had pruritus-related sleep disorders . It has also been observed that patients with poor sleep quality caused by moderate to extreme pruritus, have a higher risk of mortality . In Stage 5 CKD patients, 61% experienced difficulty falling asleep because of pruritus, while 44% experienced sleep disruptions due to itchy sensations . In Pakistan, the prevalence of CKD-aP ranges from 64.64–77.7% [15, 16]. Pisoni et al found that the prevalence of moderate to severe pruritus due to CKD was 45% in the Dialysis Outcomes and Practice Patterns Study (DOPPS) I (1996–2001), while in the DOPPS II (2002–2004) it was 42%, however, 45% of patients experienced poor quality of sleep . Poor quality of sleep in turn has been linked to an increased risk of hypertension , CKD-aP [18, 19], impaired glucose tolerance , diabetes mellitus , depression , impaired HRQOL, increased mortality rate , and increased healthcare utilization .
A multicenter cross-sectional study was undertaken to estimate the burden and impact of pruritus on the sleep quality of CKD-aP among patients undergoing hemodialysis from July 2016 to April 2017 at tertiary-care hospitals, namely the Institute of kidney diseases, Peshawar and the Pakistan Kidney Patients Association, Rawalpindi Pakistan.
A total of 354 patients were recruited (response rate = 100%). The flow on how patients were recruited is shown in (Fig 1). The majority were male (66.1%) and the median [IQR] age of patients was 42.0 [34.0–50.0]. The age of patients, duration of having CKD and being on dialysis was significantly higher in patients with pruritus. Hypertension (n = 215), diabetes mellitus (n = 47), hyperlipidemia (n = 25) and cardiovascular diseases (n = 7) were the most common co-morbidities observed in CKD patients with pruritus (Table 1). Laboratory parameters are shown in (S1 Appendix).
CKD-aP is one of the most frequent complications observed in hemodialysis patients. In previous studies, the prevalence rates of CKD-aP among hemodialysis patients differed, ranging from 22% to 84% [31–33]. The prevalence rate of CKD-aP in this study was 74%, however in our pilot study done to validate the 5D-itch scale in Urdu, we found a prevalence rate of 70% in Pakistan , which appeared to be almost similar with previous studies done in Pakistan i.e. 64% , 64.64% , and 77.7% . The severity of CKD-aP, as reported in our findings, shows that 56.5% of respondents were having moderate pruritus, followed by 34.4% with mild pruritus, and 9.2% with severe pruritus; however, our pilot study revealed that 14% had mild pruritus, 50% had moderate pruritus, while 14% had severe pruritus. . Yet another study in Pakistan reported almost similar patterns of pruritus severity with 50%, 28%, and 14% of respondents having mild, moderate, and severe pruritus, respectively . Other cross-sectional studies in Turkey also showed a high prevalence of 85.4% , and 53.4% , respectively. However, 50.4% of patients experienced moderate pruritus, and pruritus led to sleep disturbances in 33.8% of patients . In our study, a longer duration of CKD and hemodialysis had a very negligible effect on pruritus, which differs from another study in which a duration of hemodialysis of more than 2 years resulted in higher rates of pruritus (75% vs 25%) compared to those doing hemodialysis for less than 2 years . The variation in pruritus prevalence reported in different studies may be due differences in study designs, selection of participants (e.g., study populations, races, and sample sizes), and the definition of CKD-aP . In our study it was also revealed that hemodialysis machines were limited, and pressure from too many patients was a contributing factor to inadequate hemodialysis. Similar findings were reported by Chauhan et al in India, which has a similar socioeconomic status as Pakistan, and which also faces the same problem of increasing patient numbers and insufficient hemodialysis machines . The European guidelines recommend a minimum of three hemodialysis sessions per week totaling at least 12 hour with i.e. Kt/V of at least 1.2 each session (where K is dialyzer clearance of urea, t is dialysis time, and V is volume of distribution of urea) . A higher Kt/V has been associated with reduced pruritus in the majority of observational studies [5, 42, 43].
Overall, the findings of this study showed that the prevalence of CKD-aP is high among hemodialysis patients. CKD-aP has a negative impact on sleep quality among hemodialysis patients having CKD-aP, and showed positive associations with poor sleep quality.