Outcome of hemodialysis in elderly diabetic patients: a single-center experience

Background The optimal renal replacement therapy for elderly patients is unclear, and literature is evolving in this regard. For elderly individuals who progress to CKD5, hemodialysis is often a valuable treatment option. Although hemodialysis is a life-sustaining therapy and extends life, it may also create, increase, or prolong suffering in selected subgroups of geriatric patients. In our current study we focused on elderly diabetic patients above 65 years, as they constitute the more vulnerable subgroup, having multiple comorbid conditions. The primary objective was to study the patient′s survival and the association with different comorbidities. Patients and methods We conducted a retrospective analysis of 48 type 2 diabetic patients aged above 65 years. We reviewed their survival data and comorbid conditions - namely, vascular, cognitive, and autonomy. Results and conclusion The mortality rate was 7.5% per year with significant association with prior cerebrovascular accident, cognitive impairment, and lost autonomy.


Introduction
Nephrologists have recognized that the number of elderly patients with chronic kidney disease stage 5 (CKD5) has been increasing over the past 5 years [1]. Th e European registry shows that 48% of new dialysis patients are above the age of 65 and have a 2-year survival rate of 51% [2,3].
Th e optimal renal replacement therapy for elderly patients is unclear, and literature is evolving in this regard. Th e concept of maximal conservative management or even withdrawal of dialysis is under active discussion among nephrologists. Th e rationale behind this is that elderly patients not only suff er from CKD but also from varying degrees of frailty and additional comorbidities. In such situations, initiation of renal replacement treatment might not be the best option as it might not improve the quality of life, nor improve survival [4,5].
In our current study we tried to focus on elderly diabetic patients above 65 years, as they constitute the more vulnerable subgroup, having multiple comorbid conditions. Th e primary objective was to study the patient's survival and the association with diff erent comorbidities.

Patients and methods
As per hospital ethical and research committee and also as per international research ethics code no consent is required for retrospective archived fi le research.
We conducted a retrospective study reviewing the patients admitted to the Dialysis Unit at Dr. Erfan and Bagedo Hospital over 2007-2013 after obtaining approval from the ethical committee of the hospital.
We excluded patients with a history of malignancy, patients with diseases requiring immunosuppressive treatment, and those who died within three months of initiation of treatment.
A total of 48 patients were identifi ed with a mean age of 70.8 ± 4.7 years and a mean duration of dialysis and follow up of 32 ± 18 months.
Patient fi les were reviewed for: (1) Vascular access.
(2) Comorbid conditions such as coronary artery disease (CAD), peripheral vascular disease (PVD), and cerebrovascular disease. Documenting of comorbidities depended on diagnoses established

Outcome of hemodialysis in elderly diabetic patients: a single-center experience
Hatem Darwish, Ahmed Fathi

Background
The optimal renal replacement therapy for elderly patients is unclear, and literature is evolving in this regard. For elderly individuals who progress to CKD5, hemodialysis is often a valuable treatment option. Although hemodialysis is a life-sustaining therapy and extends life, it may also create, increase, or prolong suffering in selected subgroups of geriatric patients. In our current study we focused on elderly diabetic patients above 65 years, as they constitute the more vulnerable subgroup, having multiple comorbid conditions. The primary objective was to study the patient's survival and the association with different comorbidities.

Patients and methods
We conducted a retrospective analysis of 48 type 2 diabetic patients aged above 65 years. We reviewed their survival data and comorbid conditions -namely, vascular, cognitive, and autonomy.
by the corresponding specialty and appropriate imaging studies. (3) Autonomy, whether independent, wheel chair dependent, or completely bedridden. (4) Cognitive functions and depression as documented by psychiatric evaluation and medications.

Statistical analysis
Data were analyzed using an IBM computer with statistical package for the social sciences (SPSS, version 12; SPSS Inc., Chicago, Illinois, USA) as follows [6]: (1) Description of quantitative variables as mean, SD, and range.
(2) Use of the unpaired t-test to compare quantitative variables in parametric data (SD<50% mean).
(3) Use of the Mann-Whitney test instead of the unpaired t-test when SD was greater than 50% of the mean. (4) Use of the χ 2 -test to compare qualitative variables between the two groups. (5) Use of the Fisher exact test instead of the χ 2 -test when one expected cell was less than 5.
P values greater than 0.0 5 were considered insignifi cant.
P values less than 0.05 were considered signifi cant.
P values less than 0.01 were considered highly signifi cant.

Results
Tables 1-3 show the demographic and comorbid conditions of the studied cohort.
Tables 4-7 show the association of depression, cognitive stat, autonomy, and mortality. Our results showed signifi cant association between previous cerebrovascular accident (CVA) and lost autonomy and mortality (Tables 6 and 7), and no association of sex, vascular access, PVD, or mortality.

Discussion
In our studied cohort, the cutoff age for being considered elderly was 65 years. Th is cutoff point, which defi nes elderly, is debatable and inconsistent in diff erent authorities. Th e common use of a calendar age to mark the threshold of old age assumes equivalence with biological age; yet at the same time it is generally accepted that these two are not necessarily synonymous.
While the WHO considers 60+ as the cutoff point, most developed countries have accepted the chronological age of 65 years as a defi nition of 'elderly' or older person [7-9].
Taking into consideration the economic and cultural status of the Kingdom of Saudi Arabia, it was more appropriate to apply the age of 65+ to defi ne elderly.
Our study showed a mortality of 20.8% (10/48 patients) with a mean duration of 32.4 months for hemodialysis (7.55% per year). Th e mortality was signifi cantly correlated with prior CVA, lost autonomy, and cognitive impairment.
Survival data for elderly diabetic patients are seldom reported separately [10].
In elderly persons, mortality rates worsen with kidney disease more than in other groups. In the general US Male patients constituted more than 52% of the studied patients, with average age of 70.8 years. CAD, coronary artery disease; CVA, cerebrovascular accident. The majority of patients had either fi stula or graft, whereas 8.3% of them were using a catheter. IQR, interquartile range.  [13].
Th e incidence of stroke is much higher in CKD patients than in the general population. Th e United States Renal Data System (USRDS) and National    Hospital Discharge Survey (NHDS) data sets show that the incident dialysis population suff ers from a 5-10-fold higher risk of hospitalized stroke in comparison with the non-CKD population [14]. Th e short-term and long-term mortality associated with stroke appears to be higher in CKD patients than in the general population. In the Okinawa Dialysis Study (OKIDS), the 30-day stroke mortality rate was higher in CKD patients compared with the rate observed in the general population in Okinawa, Japan [15]. In a recent study from Taiwan, among 5672 maintenance hemodialysis patients, 650 (11.5%) patients had prior stroke and were found to have a 36% increased risk for mortality compared with those without prior stroke (HR 1.36, 95% CI 1.22-1.52) [16].
Cognitive disorders have long been recognized as a complication of CKD5 and its treatment. Th e prevalence of cognitive impairment, as assessed using neuropsychological tests among patients with CKD5, ranges from 16 to 38% depending on the sample and the defi nition of impairment [17]. Dementia increases the risk for poor outcomes, including disability, hospitalization, withdrawal from dialysis, and death [18][19][20].
To emphasize the importance of mobility and autonomy in dialysis patients, McAdams-DeMarco et al. [21] enrolled 146 incident hemodialysis patients and followed them up for around 30 months. Th ey found that adults of all ages undergoing hemodialysis have a high prevalence of frailty, more than fi ve times as high as community-dwelling older adults. In this population, regardless of age, frailty is a strong, independent predictor of mortality and number of hospitalizations [21].
In a French study, Couchoud et al. [22] established and validated a bedside scoring system for predicting 6-month mortality in elderly hemodialysis patients. Dependency for transfer was given the highest score of 3 points, compared with diabetes, which was given only 1 point [22].
Vascular access is an important predictor of death in hemodialysis patients. Th e relative risk for death is increased 2-3-fold in incident patients using catheters compared with those using an arteriovenous access (fi stula or graft) [23].
In our study, vascular access had no signifi cant survival outcome. Th is may be explained by the small number of patients with a catheter (4/48 patients, 8.3%).
For elderly individuals who progress to CKD5, hemodialysis is often a valuable treatment option.
Although hemodialysis is a life-sustaining therapy and extends life, it may also create, increase, or prolong suff ering in selected subgroups of geriatric patients. In fact, hemodialysis has the attributes of a serious and progressive chronic illness; it may correct uremia, but the disease pathway of the elderly continues [24,25]. In our studied cohort of patients, there was signifi cant association between both CAD and PVD and cognitive function impairment. Th is may be because both stem from a common pathological pathway, atherosclerosis, which is well established and has its unique traditional and nontraditional risk factors in CKD patients, especially when diabetes is the etiology of CKD. Moreover, dialysis itself is associated with a signifi cantly increased risk for worsening vascular disease. Registry data and data from observational cohort studies suggest that coexisting vascular disease, whether CAD, PVD, or cerebrovascular disease, is associated with increased mortality risk for patients on dialysis [26,27].
In conclusion, our study showed a mortality rate of 7.5% in elderly diabetic patients above 65 years. Th e mortality in such a high-risk group was signifi cantly associated with CVA, cognitive impairment, and lost autonomy.
Th e limitations of our study include its retrospective nature and the limited number of patients.
Nephrologists require more data on renal replacement options in the elderly, as well as on outcome from diff erent options. From this point of view our study might be useful but defi nitely we are awaiting largescale studies better characterizing this heterogeneous risky group as well as guidelines for treatment options and outcome.