Risk Factors for Diabetic Complications among Diabetic Patients, Chirumanzu District, Zimbabwe, 2011

  

    
Risk factor
    
Odds ratio
    
95% C.I
    
Z statistic
    
P-value
  
  

    
Eating sugar containing diet
    
2.19
    
0.44-10.73
    
0.963
    
0.336
  
  

    
Type of treatment (Oral tablets/Insulin)
    
0.08
    
0.01-0.65
    
-2.36
    
0.018
  
  

    
Duration of diabetes(newly diagnosed/Already on treatment)
    
9.989
    
0.91-109
    
1.89
    
0.059
  
  

    
Uses treatment assistant (Yes/No)
    
0.621
    
0.156-2.641
    
-0.645
    
0.519
  
  

    
Missed treatment doses (Yes/No)
    
7.974
    
1.599-39. 78
    
2.532
    
0.0113
  
  

    
Age at diagnosis
    
1.1304
    
0.9556-1.331
    
-1.4305
    
0.1526
  
  

    
Co-morbidity with hypertension (Yes/No)
    
31.3664
    
3.5810-74.744
    
3.112
    
0.0019
  
  

    
Hospital used
    
3.7613
    
0.547-25.86
    
1.347
    
0.1781
  
  

    
Distance from hospital >5km
    
5.6652
    
2.404-13.35
    
3.7025
    
0.0001
  
  

    
Ever failed to pay for treatment (Yes/No)
    
46.5761
    
5.9891-362.23
    
3.670
    
0.0002
  

Table 3:  Independent risk factors associated with developing diabetic complications, Chirumanzu District, Zimbabwe; 2011.

The majority (78.7%) of cases and controls were aged between 40 and 69years and their ages were comparable, median ages of 51.5(Q1=43, Q3=61) and 52.5(Q1=43.5, Q3= 60.5) respectively. The majority of the study participants were female for both cases and controls, accounting for 63.3% of participants. There was however no significant gender difference between cases and controls. The highest level of education attained by cases and controls was comparable and so was religion.

Out of the 68 cases of diabetic complications, 44 (64.7%) had severe hyperglycemia, 36 (52.9%) had nephropathy, 12 (17.6%) had diabetic foot and 7 (10.3%) had hypoglycemia. Seventeen (25%) had both severe hyperglycaemia and nephropathy, 7(10.3%) had both nephropathy and diabetic foot and 6 (8.8%) had both severe hyperglycaemia and diabetic foot.

Only 81(59%) out of the 136 study participants were normal weight by Body Mass Index (BMI). Twelve (8.8%) were underweight, 30 (22.1%) were overweight and 13 (9.6%) were obese. Thirty-one (45.6%) of the cases were at least overweight (overweight plus obese) while 12 (17.6) of the controls were at least overweight. Nine (13.2%) of the cases were obese while 4 (5.9%) of the controls were obese.

Knowledge on the broader aspects of diabetes, diabetic care and complications was generally high among both cases and controls, only slightly higher among controls than cases except for the possible complications of diabetes mellitus. The majority (>94%) of cases and controls knew that diabetic patients should not take a sugarcontaining diet, that DM was essentially elevated blood sugar, that DM treatment is taken for life and that DM is a non-communicable disease. A lower proportion (82.4%) of study participants knew that adherence to treatment is essential to minimize diabetic complications and an even lower proportion (67%) knew at least 2 (two) possible complications of DM.

The knowledge about the possible complications of diabetes was generally low among both cases and controls except for diabetic coma which was reported by three quarters (75.7%) of study participants. However, the knowledge of possible complications was slightly higher among controls than among cases for all possible complications reported by study participants except for renal failure which was reported by more cases than controls.

More controls (73%) used treatment supporters than cases (49%). Controls also used other therapies like prayers, herbs and/or traditional medicines more than their counterparts. However, more cases (63%) missed their doses than controls (20%) did and they also took sugar containing meals more than their counterparts (55% and 22% for cases and controls respectively). There were more smokers among the cases than the controls. Thus, more cases had bad practices than their controls.

Being unmarried (single, divorced or widowed) was positively associated with developing diabetic complications such that those who were unmarried were 3.68 times more likely to develop diabetic complications than those who were married and this was statistically significant with a p-value of less than 0.001. Being a widow was associated with a 2.93 times more risk of developing diabetic complication than their counterparts who were not widows and this was also statistically significant with a p-value of 0.013. Having attained at most primary education and residing in an urbanized residence were significant risk factors for developing diabetic complications with odds ratios of 2.83 and 2.48 respectively and p-values of 0.005 and 0.01 respectively.

Health education was protective against the development of complications of diabetes mellitus. Those who had been given health education were 73% less likely to develop diabetic complications than those who had not received it and this was statistically significant with a p-value of less than 0.001.

Eating a sugar containing diet was a significant risk factor for developing diabetic complications such that those who had a taken a sugar containing meal in the preceding month were 3.9 times likely to develop complications than those who did not. This was statistically significant with a p-value of less than 0.001.

There was a positive association between smoking and the development of diabetic complications with an odds ratio of 2.19 but this was not statistically significant (p-value 0.082)

The use of insulin as a treatment regimen was associated with the development of diabetic complications. Patients who were on insulin were 3.83 times more likely to develop complications than those who were on either dietary control or on oral tablets with a statistically significant p-value of less than 0.001.

Missing treatment doses was associated with a significant 6.63 times increase in the risk of developing complications with a p-value of less than 0.001. Diabetic patients who also suffered from hypertension had a 4.10 fold risk of developing diabetic complications as compared to their counterparts who did not have hypertension. This was significant, with a p-value of 0.001.

Being on treatment for diabetes was a protective factor such that those who were already on treatment were 64% less likely to develop complications than those who were newly diagnosed, with a significant p-value of 0.0087. Having a treatment supporter was also protective with an odds ratio of 0.24 and a p-value of less than 0.001.

Diabetic patients who used the government hospital for their treatment were 2.26 times more likely to develop complications than those who used mission hospitals. This was statistically significant with a p-value of 0.023. Distance from hospital was also significantly (p-value < 0.001) associated with the development of complications with patients residing 5km or more from the hospital where they get their supplies 3.97 times more likely to complicate than those who resided within 5km radius.

Those who had failed to get their supplies from their hospital had a 3.12 fold increased risk of complications than those who had never failed to get their supplies in the past 1year (p-value 0.0015)

The association between missing treatment doses and developing diabetic complications was modified by gender such that males who missed their doses were 15.6 times more likely to develop complications whereas females who missed their doses were 4.3 times more likely to develop complications.

The association between eating a sugar containing diet and developing diabetic complications was modified by having been given health education before such that those who received health education and those who did not were 1.7 and 5.9 times likely to develop diabetic complications respectively.

The association between the use of a treatment supporter and the development of diabetic complications was confounded by the type of treatment such that those who used a treatment supporter were 67% less likely to develop diabetic complications than those who did not. The protective effect of using a treatment supporter remained statistically significant in insulin users but non-significant in oral tablets users.

The association between distance from hospital and developing diabetic complications was modified by missing treatment doses such that patients staying 5km and more from the hospital who missed their treatment doses were 2.47 times more likely to complicate whereas those staying within 5km who missed their doses were 5times more likely to complicate than those who did not.

The association between co-morbidity with hypertension and the development of diabetic complications was confounded by the type of treatment such that those who had hypertension were 11.45 times more likely to develop complications than those without hypertension.

After logistic regression, the independent risk factors for developing diabetic complications among diabetic were; type of treatment (Oral tablets or insulin), missed treatment doses, comorbidity with hypertension and having failed to pay for treatment.

Diabetes mortality data was not available for the year 2011 because the hospitals had not submitted the data to the district. Two (2) of the 3 hospitals had not compiled the data by the time of data collection.

However for the year 2010, there were 410 patients recorded in the diabetic registers of the district. During the year, the district recorded 52 deaths due to diabetes and its complications. It was however not possible to disaggregate and quantify the actual causes of death among diabetic patients because the majority of deaths were not specified and had diabetes only as the direct cause of death.

Discussion

The majority of study participants were female (63.3%). This shows that in this group of patients, diabetes has a female bias, contrary to the WHO reports and many other studies that showed that there are few gender differences in the prevalence of diabetes mellitus. Among different studies, prevalence rates of diabetes are not consistently higher for women, with the ratio of the prevalence in women versus men varying among populations studied, probably due to different distributions of risk factors such as body mass index, physical activity, and genetic differences.

This finding was however consistent with Gale E.A.M. and Gillespie K.M. in 2001 who reported that the overall sex ratio is roughly equal in children diagnosed under the age 15 but while populations with the highest incidence all show male excess, the lowest risk populations, mostly of non-European origin, characteristically show a female bias. In contrast, male excess is a consistent finding in populations of European origin aged 15-40years, with an approximate 3:2. Male: Female ratio [5].

In this study however, the higher proportion of females could reflect their general excess in the Zimbabwean population, estimated to be 51% female against 49% male. The proportion of female was even higher among the cases at 69.1%, showing some association (though statistically insignificant) between female gender and diabetic complications, consistent with WHO reports that there are some gender differences seen in acute and chronic complications of the disease [5].

The United States National Hospital Discharge Survey of 1989- 1991 showed that almost twice as many women were discharged with the diagnosis of nonketotic hyperosmolar coma than men [6] The number of women discharged with hypoglycemia was almost 1.5 times that of men [7]. In another population-based study, the rate of diabetic acidosis in females was 1.5 times that of males [8].

Half (50%) of study participants were on insulin while only 4(2.9%) were on dietary control. It was not possible to differentiate between those who had type 1 and type 2 diabetes because this was not recorded for most of the patients, some patients had been changed from oral hypoglycemics to insulin and the necessary definitive diagnostic tests were not available. However, it is expected that about 5-10% of patients are type 1 diabetics.

The majority (78.7%) of cases and controls were aged between 40-69 years with median ages of cases and controls of 51.5years and 52.5years. these findings are consistent with the WHO report which states that most people with diabetes in low and middle income countries are middle-aged (45-64years) and not the elderly (65+).3 This could have serious adverse effects on the patients, their families and the country at large since this is a productive age group which could suffer loss of considerable productive time due to morbidity and loss of family income in paying for their treatment which is relatively expensive and lifelong.

Ninety-five (95%) of diabetic patients under study attained at least primary level education. This could improve their understanding of their condition and treatment, possibly increasing cooperation and compliance, hence outcomes of management and reduction in incidence of diabetic complications. Those who attained at most primary education were more likely to develop complications compared to those who attained at least secondary education. This demonstrates the importance of education in the management and control of diabetes.

Being unmarried was significantly associated with the development of diabetic complications in this population. This suggests lack of family support, ranging from emotional, financial and treatment support and possible concomitant depression playing a role in the development of complications. A study done in the United States of America showed that the risks of comorbid myocardial infarction, hypertension, arthritis, and angina were significantly higher in the presence of concomitant depressive symptoms, as were the risks of diabetic complications, functional disability, incontinence, vision impairment, poorer perceived health status, and health service use among both diabetic and non-diabetic individuals [9].

Widowed patients were more likely to develop complications suggesting the effects of the loss of a life partner on diabetes care. This could be attributed to depression, anhedonia and the reduction in the support that used to be available from the partner.

Residing in an urbanized residence had a significant association with the development of diabetic complications, supporting the long standing fact that diabetes and its complications are problems of the more affluent although recent studies have shown an increasing incidence of these conditions in rural populations. Patients residing in urbanized residence tend to leave a more sedentary lifestyle with less physical activity as compared to those living in rural settings. Those living in rural settings tend to do more manual work in fetching firewood and water and in undertaking subsistence farming. There is also an increased likelihood of eating a high sugar and high cholesterol diet among the urbanized because of the ready availability of these foods and the use of refrigerators whereas rural residents eat a more natural food and vegetable based diet [10].

Employment was however not associated with developing diabetic complications. The major form of employment in this population, mainly farms, mines and small scale enterprises are largely manual in nature, increasing physical activity which reduces the risk of developing complications.

Being at least overweight (overweight or obese) was significantly associated with developing diabetic complications. Excess body fat and obesity increases the incidence and extent of insulin resistance. This, coupled with the likely lack of exercise and physical activity, and co-morbid conditions like hypertension which are more common in the overweight and obese, exacerbate the effects of elevated blood sugar, increasing the likelihood of developing diabetic complications. There was an insignificant association between obesity alone and diabetic complications. This is probably because of the small number of patients who were obese. A larger sample size would perhaps yield a significant positive association.

Insulin therapy was strongly associated with the development of diabetic complications as compared to oral hypogycemic therapy. It is known that insulin therapy is necessitated by the severe deficiency of insulin in the body but the exact levels, which are difficult to determine and to monitor, vary between individuals. This makes it difficult to titrate the amount of insulin required by individuals, resulting in unstable glycaemic control leading to either hypoglycaemia or hyperglycaemia. As such, patients are prone o under-dosage and over-dosage alike, predisposing them to complications. Missed treatment doses also lead to complications more commonly with insulin therapy than with oral drugs. Studies in Kenya also revealed similar findings, were patients on insulin were more likely to develop diabetic ketoacidosis and hypoglycaemia [11,12].

The lack of health education on diabetes was significantly associated with the development of complications probably largely because of the lack of understanding of their condition and the requirements for proper care and treatment. Similar findings were reported by Gayle E. et al in 1992 and Flores Rivera in 1998 where lack of previous outpatient health education was significantly associated with amputation in patients with diabetes mellitus [13].

Patients who were non-compliant with the diabetic diet were more likely to develop complications than those who were compliant. Eating a sugar containing in diabetic patients overwhelms the already depleted insulin levels and adversely affects glycaemic control, increasing the risk of developing diabetic complications. Studies in South Africa, Tanzania and Kenya have shown that strict dietary control significantly reduces the risk of developing diabetic complications.

Matthew E. Kahn reported that diet adherence is a key determinant in minimizing the risk of diabetic health complications. Diabetics who ignore their doctor’s advice, concerning diet, smoking and exercise, are taking a gamble. Food product innovation, improved understanding about the benefits of tight diabetic compliance, and increased information dissemination all provide incentives for diabetics to modify their behavior [14].

The control of diabetes is hinged on dietary control and strict adherence to treatment. Missing treatment doses was significantly associated with the development of complications as this affects glycaemic control, leading to persistent hyperglycaemia, hence diabetic complications. Otieno C.F. and Kayima J.K et al in Kenya in 2005 found that missing insulin doses was significantly associated with diabetic ketoacidosis. They also found out those who were newly diagnosed were more likely to develop diabetic complications than those on treatment. In this, study, newly diagnosed patients were more likely to develop severe hyperglycaemia. This is mainly because most patients have diabetes but are unaware of it and already have one of the diabetic complications at presentation to a health facility where the diagnosis can be made [11].

Diabetic patients who were also hypertensive had an increased risk of diabetic complications compared to their non-hypertensive counterparts. Although high blood pressure causes few symptoms, it has two negative effects: it stresses the cardiovascular system and speeds the development of diabetic complications of the kidney and eye [1].

Accessibility of health services remains a problem especially in rural settings were patients have to travel long distances to access health care. This increases the chance of them delaying to seek health care services and defaulting treatment, particularly chronic disease patients. Diabetic patients who live more than 5km away from the hospital were more likely to complicate probably because of these factors.

Failures to pay for treatment services and to get drugs from health facilities are likely to have caused patients to miss their doses, increasing their risk of developing diabetic complications.

References

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