Division of Nephrology, Department of Medicine, Chris Hani Baragwanath Hospital Renal Unit, University of the Witwatersrand, Soweto, South Africa
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Abstract |
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Methods. We report a prospective study in a large African tertiary hospital and its community based satellite clinics. Infection rates as well as factors that may influence them were studied. Sites of infections were documented and causes of CAPD failure recorded. All patients qualifying for dialysis from January 1998 to July 1999 were included.
Results. Eighty-four patients were enrolled. There were 55 males and 29 females. The mean age was 39±10 (range 1671) years and mean duration on dialysis at the end of the trial period was 17 months. The peritonitis rate was one episode every 27.9 patient months. Attrition to haemodialysis occurred in 16.6% of patients (n=14) and loss to follow-up in 29.8% (n=25). Fourteen patients regained renal function or were transplanted. Peritonitis appeared to be related to a poor BAD-C score (Bara Adapted Dialysis Compliance), i.e. combination of clinical status and clinic visits (P=0.07). The odds ratio for failure of CAPD with peritonitis was 5.3 times higher (confidence interval (CI) 1.717.1; P=0.0085). A low BAD-C score was a significant indicator of CAPD failure (P=0.0001). The natural turnover rate of patients was 46%. Home conditions, employment, and education levels did not correlate with CAPD failure.
Conclusion. The peritonitis rate and aetiology are similar to the developed world. Socioeconomic factors did not appear to play a role in peritonitis rates or CAPD failure.
Keywords: Africa; CAPD; dialysis failure; peritonitis; socioeconomic factors
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Introduction |
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Haemodialysis (HD) positions on the program are at maximum capacity and scarce resources make it difficult to establish more HD units. They are more expensive to run and require specialized expertise [4].
Infections are a major cause for terminating this form of dialysis [57]. Previous studies have found that socioeconomic factors, lack of transportation, poor housing, and inadequate formal education and race may limit the success of CAPD [8,9]. Peritonitis rates were found to be influenced by occupant-to-bedroom ratios and housing conditions [8]. Limited success with CAPD in black patients and high peritonitis rates has been described [8,9].
This study was carried out to determine the rate and factors that may influence the onset of peritonitis, the attrition rate and loss to follow-up while on the CAPD programme. There is also limited data in the literature on CAPD in Africa.
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Subject and methods |
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The data was collected during routine follow-up visits at the clinics and hospital. Detailed histories and physical examinations were carried out when the patient was admitted to the programme and then whenever necessary. Laboratory investigations were carried out when indicated and as per management protocols. Routine questioning when being accepted onto the programme assessed socioeconomic circumstances such as home conditions, employment, and level of education.
Housing type was defined as brick if the living area was predominantly built of brick. A shack if the housing was of an informal type made of predominantly corrugated iron. A flat was defined as a dwelling in an apartment building and a room if the patient lived in a single room in a house, attached to a house and/or at their place of employment and only if it was made of brick or concrete. Personal hygiene was defined as their physical appearance, i.e. condition of clothes worn and on assessing their ability to access a bath or shower. Housing and hygiene was grouped together as home conditions.
Technique evaluation was carried out by looking at the way they changed their bags, i.e. hand washing and bag connection and disconnection procedures and compared with the taught method when the patient started CAPD. This was done at the time of peritonitis infection. These were subjective assessments by experienced nurses or doctors and evaluated as excellent, good, fair, and poor. Adequacy, compliance, and outcomes were assessed during the clinic visits or at time of admission to hospital. Due to limited resources, adequacy is measured by evaluating the patients clinical status, i.e. achieving dry weight; creatinine levels (<1200); calcium phosphate product less than 5 and haemoglobin levels 810 g/dl. Kt/V adequacy testing was not used. Excellent adequacy was defined as achieving all acceptable clinical parameters (four out of four) 90% of visits, good as most of these parameters (i.e. three out of four, 7089% visits); fair as some of the parameters (two to three out of four, 5069% of visits); and poor almost none (one to two out of four, <50% of visits). Patients are required to be seen at clinics monthly. Patients attending at least 90% of clinic visits were considered as having excellent compliance, 7089% as good compliance, 5069% as fair, and less than 50% as poor. The patients clinical status and clinic attendance was combined and graded together as excellent, good, fair and poor, according to the combined percentage score, and this score is referred to as the Bara Adapted Dialysis Compliance scoring system (BAD-C).
Peritonitis and infection rates were calculated as new incidents occurring per patient months during the study period. Infections that did not resolve on therapy were considered as single episodes but if they occurred after a negative culture post completion of therapy then it was considered as a separate infection. Patients were considered to have peritonitis if two of the following findings were present: abdominal pain, cloudy bag fluid, or leukocyte count >100/mm3; or positive culture from bag fluid.
When evaluating the causes for failure of CAPD, there were a number of reasons found. These failures were defined as attrition if the patients were transferred to HD. Lost to follow-up indicated that they regained renal function or were transplanted, non-compliant, transferred to another programme, or they died. The combination of attrition and loss to follow-up were considered as the natural turnover rate (NTR) of CAPD, and was expressed as a percent of the total patients on the study.
Statistical analysis (lower significance level, P<0.05) was performed using 2 test to assess proportions, where appropriate these results were presented as odds ratios with 95% confidence intervals (CI). A MannWhitney U test was used for continuous variables (e.g. age). The peritonitis rate was calculated directly from the number of infections over the period and from the number of months each patient was on dialysis. A computer based kinetic modeling and the Statistica check citation computer programs were used for analysis.
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Results |
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Table 3 reflects the number and type of infection for the patients on the programme. The peritonitis rate was found to be one episode every 27.9 patient months. There were a total of 34 peritonitis episodes. Six of these patients discontinued CAPD because of their peritonitis and 12 continued on the programme after treatment. Staphylococcus aureus was the commonest cause of peritonitis infection in 79% of the cases with Staphylococcus epidermidus and psuedomonas following at 6%. The total number and causative organism of the peritonitis infections are outlined in Figure 1
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A total of 14 patients had technique failure resulting in transfer to HD. Eleven of these were due to infection, six peritonitis and five tunnel infections. Of the peritonitis patients, two had recurrent peritonitis complicated by social problems, which warranted changing them to HD. Two patients had a Psuedomonas infection and one had tuberculosis peritonitis. They were treated for their infection but did not continue on CAPD. Five of the seven patients with a tunnel infection were transferred to the HD programme due to non-response to antibiotic therapy. One of the patients had both a tunnel infection with peritonitis (Pseudomonas) and one had peritonitis and an exit-site infection (S. aureus). The other causes of attrition to HD included non-compliance (n=2) and deteriorating eyesight from diabetes (n=1).
When evaluating possible causes for peritonitis infections, fewer clinic visits and a poor clinical status, i.e. a poor or fair BAD-C score, appeared to be a factor for developing peritonitis (P=0.07). However, the odds ratio for failure of CAPD with peritonitis was 5.3 times higher (95% CI 1.717.1; P=0.0085). Factors such as gender, education, and home conditions were not found to influence the onset of peritonitis. However, if the technique was not evaluated as excellent they had an odds ratio of 9.1 for CAPD failure (95% CI 2.534). However, no correlation existed between type of house and bag-changing technique.
A total of 25 patients (30%) were lost to follow-up. Positive losses were considered to be those patients who regained renal function (n=8) while on CAPD and those (n=6) who were transplanted. These amount to 14 patients (16.6%). The negative losses are those patients who were unable to continue with CAPD because they died (n=7, 8.3%), refused treatment or were non-compliant (n=4, 4.8%). Of those patients who died, some of the causes were unrelated to their renal failure, e.g. HIV related illness. Three patients developed HIV after being accepted on the programme. Transfusion was not a cause of this infection. One patient was transferred to another city as he was relocating to that area. Compliance was an important problem resulting in peritonitis and CAPD failure (n=6; 7.1%). All reasons for CAPD failure, i.e. technique failure (attrition) or loss to follow-up are outlined in Figure 2.
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On evaluation of the reasons for CAPD failure, a poor BAD-C score was found to be the most critical factor (P=0.0001) (Figure 3) and a less than excellent bag-technique was also a significant factor (odds ratio 9.1; CI 2534). Peritonitis appeared to be an important factor (P=0.07). However, gender, age, and home conditions did not appear to influence CAPD failure. Other socioeconomic factors such as education, and employment status were also not found to be significant.
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Discussion |
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Socioeconomic factors did not appear to play a significant role and, therefore, peritonitis rates appear to be due to other factors. There is 49% unemployment on the programme, which has not improved compared with earlier studies [1,2]. The average earnings were below US$60 per month but this and unemployment were not significant factors in peritonitis, as in other studies [8,12]. The fact that socioeconomic factors like home conditions, education, employment, and earnings did not influence onset of peritonitis is particularly important in our programme and is especially relevant for other developing countries.
The improvement seen in this study compared with an earlier study may be related to the fact that we now use the dual bag system and have a community based training programme [8].
A fair or poor BAD-C score (adequacy and clinic visits) was associated with CAPD failure and a tendency to cause peritonitis. The BAD-C scoring system may be less specific than Kt/V and, although it is a cheaper method to evaluate patients, it still needs closer evaluation against Kt/V. A less than excellent bag-changing technique increasing the risk of CAPD failure is worrying and indicates the need for ongoing patient training, especially when presenting with an infection.
Age was not found to have an influence on peritonitis or attrition and the patients in this study were younger than in developed world programmes. An older average age at onset of ESRF programmes in developed countries is well documented [12,13]. In Africa, ESRF occurs predominantly in the younger population with an average age of between 32 and 39 years at onset [13].
The types of bacterial infections are similar to those in other studies with S. aureus being the most common infection (Figure 1) [7,14]. The types of infections resulting in PD failure are also similar to other findings (Table 3
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There is no doubt that an attrition rate and loss to follow-up (excluding regaining function and transplantation) of 36% is high. Although the infection rate was a significant contributor to failure and the attrition rate was high, this is not higher than other programmes in the developed world [57,16]. Factors such as deaths related to end-stage renal disease as well as unrelated causes are contributors to dialysis failure in all programmes [6,16,17]. It is the patients who refuse to continue on CAPD and those who are non-compliant who require specific attention.
Despite the above, CAPD remains a viable and successful form of renal replacement therapy in the developing world. It is worthy of note that there is a positive loss of 16.6%, i.e. transplanted patients and those regaining renal function. These patients are a cost saving for the health service and probably for the community as a whole and serve to reflect the benefits of the programme. This phenomenon of regaining renal function is an important one and has been documented before [19]. It is especially important in our community where hypertension is an important cause of ESRF and requires further investigation.
In the context of the South African and African experience where resources are limited, it is obvious that CAPD is a vital therapeutic option for patients with ESRF [13]. It has advantages in that it is a mode of dialysis that can be carried out in the community. It saves patients having to travel and does not rely heavily on expensive infrastructure and health professionals. So, despite the lower socioeconomic factors existing in the majority of African communities, it is still a viable form of dialysis with peritonitis rates, attrition rates, and a natural turnover rates equivalent to those in the first world [57,18]. CAPD should not be regarded as second-class treatment. Technical advances may address some of the problems related to its failure, like a high peritonitis rate and patient dropout rate, but other aspects that may prevent treatment failure need to be researched [9,20].
A comprehensive assessment programme looking at the patients medical understanding, their ability to understand the technique, their psychological make-up and social circumstances is due to be instituted. These components of the programme need attention and may further improve the success of the programme [4].
CAPD in the African context, at least in the near future, is a viable and important means of providing dialysis. This study is especially important in the context of poverty and limited access to medical resources faced by many Africans.
Hopefully, this will encourage other developing world communities to endorse CAPD as a real option for dialysis.
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Acknowledgments |
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Notes |
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References |
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