Identification of Socioeconomic Variables Responsible for Hypertensive Kidney Disease Among Bangladeshi Adults

The study was conducted to identify some socioeconomic variables responsible for the prevalence of hypertensive kidney disease among Bangladeshi adults of 18 years and above. For this, 498 males and 497 females, totalling 995 adults of both urban and rural localities were investigated. In the sample there were 17.6% hypertensive adults and 18.9% of them were suffering from hypertension and kidney disease simultaneously. Beside other percentages of respondents, there were 19.6% elderly people of ages 50 years and above, 30.2% obese adults, 67.0% diabetic patients, 44.4% involved in sedentary activity and 33.1% smokers. The overall percentage of hypertensive kidney patients was 3.3. These group of patients were discriminated from the remaining 96.7% adults. During discrimination duration of diabetes was identified as most responsible variable followed by age, body mass index, sedentary activity, smoking habit, etc. The risk of prevalence of this health problem was 12.25 times in diabetic patients suffering for 15 years and above, 8.43 times in elderly people, 16.80 times in obese adults, 2.50 times in adults involved in sedentary activity, and 1.91 times in smokers. Higher risk rate was also observed in adults of lower economic group of families.

Obesity, diabetes and hypertension are three inter related health problems and are the risk factors of many non-communicable diseases including kidney diseases [1 – 12]. Diabetes leads to kidney failure and chronic kidney disease is associated with pre-diabetes, obesity and hypertension [13 – 18]. Hypertensive kidney disease is a medical condition referring to damage of kidney due to chronic high blood pressure [19].   Hypertension can lead to severe health complications worldwide [ 20, 21]. It increases the risk of heart disease, stroke, and sometimes death [22 - 27]. The problem is recognized as modifiable risk factor for cardiovascular disease and  at an end stage renal disease [23]. But, it is the major cause of premature death worldwide [24]. Number of adults with hypertension increased from 594 million in 1975 to 1.13 billion in 2015. The increase was noted largely in low-and middle-income countries. Around 7.5 million deaths  or 12.8% of the total of all deaths worldwide occur due to high blood pressure [28]. It is predicted to be increased to 1.56 billion adults with hypertension in 2025 [29]. The risk factor of hypertension is cardiovascular and its related diseases.  Again, heart failure is highly prevalent in patients of chronic kidney disease and end stage renal disease and this problem leads to mortality [30 – 32].

The risk factors for hypertensive kidney disease is poor health management including lower control of high blood pressure  and other  kidney disorders [19]. The problem is also associated with some socioeconomic  characteristics including older age, gender variation [33]. In this paper, an attempt was made to identify some socioeconomic variables responsible for the prevalence of hypertensive kidney disease among Bangladeshi adults.

The present analysis was done using the data collected from 995 urban and rural adults of 18 years and above. The data were collected during the session 2018 – 19  by some nurses and medical assistants working in some objectively selected  diagnostic centres located in both urban and semi-urban areas of Bangladesh.  Among the respondents  498 were males and 497 were females. The ratio of males and females  were   50.1:49.9 which is the national sex ratio of Bangladesh [34].  The respondents were from both  urban and rural areas  of the country and among them  67% were diabetic patients. 

 The data on different socioeconomic variables of each selected respondent were recorded through a pre-designed and pre-tested questionnaire containing  different  questions related to residence, religion, gender, marital status, age, education, occupation, family income, family expenditure. Beside these demographic data, other information were on life-style, including involvement in physical work, smoking habit, consumption of restaurant food,  and utilization of time by the respondents.  The information of prevalence of any of the non-communicable diseases, duration of  diabetes, and the stages of treatment of the disease and the  cost of treatment  of the disease were also recorded. The collected data were recorded in both interval and nominal scales, but for ease of analysis all data were expressed in nominal scale. The data of weight ( in kg ) divided by height ( in metre2)  was  used to measure the value of body mass index (BMI) to identify obese adults(  if BMI ≥ 27.5; underweight ,if BMI< 18>

To fulfil the objective of the study, the association of each of the socioeconomic variable with the prevalence of hypertensive  kidney disease  was investigated, where significant association was decided if p-value of any Chi-square statistic ≤ 0.05 [ P(  ) ≤0.05 ]. Irrespective of significant or insignificant association, the risk ratio and its confidence interval was calculated for adults for whom prevalence of hypertensive kidney disease  was noted in higher rate for a particular level of a socioeconomic  variable. Finally, discriminant analysis  was done to select the most responsible variable for the prevalence of this health problem. The most responsible variable was identified depending on the highest absolute value of correlation coefficient of socioeconomic variable with discriminant function score [39, 40, 41]. All the calculations were done using SPSS  Version 25. 

The percentage of hypertensive adults in the sample was 17.6 and that of kidney patients was 9.2. Among the hypertensive adults 18.9% were kidney patients also [ Table 1]. The different health problem was significantly associated with prevalence of hypertension [  = 105.383, p –value=0.000 ]. The sample hypertensive kidney patients were 3.3%. They were classified into different classes according to different levels of socioeconomic variables. The classified results were presented in Table 2.   

 Table 1: Distribution of adults according to prevalence of hypertension and health problem

Table 2: Distribution of adults according to prevalence of hypertensive kidney disease and socioeconomic variables

The rural adults were 53.4% in the sample and 3.4% of them were patients of hypertensive kidney disease as against the overall 3.3% patients of these diseases. Rural and urban people were similarly exposed to this health hazard [  =0.019, p –value=0.890 ; R.R.= 1.05, C.I.( 0.40, 2.78) ]. The sample male adults were 50.1% and 3.8% of them were affected by this health hazard. There was insignificant association between gender variation and prevalence of hypertensive kidney disease but male adults were at more risk by 35% [ =  0.773, p –value=0.379 ; R.R.=1.35, C.I.( 0.69,2.66)]. The percentage of non-Muslim respondents was 14.8, but higher proportion ( 0.041) of them , though not significantly different from the corresponding proportion ( 0.032) of Muslim adults, were suffering from hypertensive kidney disease [ = 0.315, p –value=0.575 ]. But non-Muslim adults had higher risk of facing this problem by 28% more [ R.R.=1.28, C.I.( 0.54, 3.04)]. Single adults were only 6.9% in the sample, but 4.1% of them were patients of hypertensive kidney disease. For them the chance of facing this health problem was 34% more as it was for married adults [ R.R.=1.34, C.I.( 0.42, 3.88)]. However, prevalence of hypertensive kidney disease  was independent of marital status [ = 0.246, p –value=0.620 ]. The sample elderly people of ages 60 years and above were 8.0% and of ages 50 years and above were 19,6%. The prevalence rate among the above mentioned first group of adults was 17.5% and among the second group it was 13.8%. There was significant increasing trend of prevalence rate with the increase in ages [ = 89.956, p –value=0.000]. The eldest group of adults had risk of 8.43 times as it was for others and the risk of elderly group of adults was 18.46 times compared to others [ R.R.=8.43, C.I.( 4.40, 16.16); R.R.= 18.46, C.I.( 7.73,44.07)}. The percentage of primary educated respondents in the sample was 12.2 and 7.4% of them were patients of this health hazard as against the overall percentage 3.3 of sample affected adults. This group of adults were at higher risk of the problem by 94% compared to the risk of others [ R.R.=1.94,C.I.( 0.86, 4.38)]. The prevalence rate ( 3.0%) was lower among higher educated persons(57.5%). But there was no significant increasing or decreasing trend in the prevalence rate with the increase in level of education [ =7.710, p –value=0.052].  Similar insignificant rates of prevalence was noted for people of different levels of occupation [ = 3.407, p-value=0.492]. But highest rate

 ( 4.8%) was observed among agriculturists and unskilled labours ( 10.5%). This group was 93% more exposed to this health hazard [ R.R.=1.93, C.I.( 0.76, 4.89)]. Physically active persons were 48.3% ,but higher proportion ( 4.0%) of them were affected by this health hazard. For them the risk of the disease was 45% more as it was in others [ R.R.=1.45, C.I.( 0.74, 2.86)]. But prevalence was independent of physical activity [ = 1.165, p –value=0.280].  The percentage of respondents involved in sedentary activity was 44.4 and 5.0% of them were facing the problem of hypertensive kidney disease. They were more exposed to this health hazard by 2.50 times compared to others [ R.R.=2.50,C.I.( 1.22, 5.10)].  The prevalence was significantly associated with utilization of time [ = 6.841, p –value=0.009 ].

The respondents from lowest income group of families was 39.1% and 4.8% of them were suffering from hypertension and kidney disease simultaneously. Their chance of facing the problem was 87% more as it was for others [ R.R.1.87, C.I.( 0.96, 3.71)]. Though not significant the prevalence rate was in declining trend with the increase in level of family income [ = 4.044, p –value=0.257]. Almost similar was the case in respect of family expenditure [ = 2.281, p –value= 0.516]. The adults from families spending lowest amount of money as family expenditure was 41.4% and prevalence rate among them was 4.1%. For them the chance of prevalence was 48% more as it was for others [ R.R.=1.48,C.I.( 0.76, 2.89)]. The sample process food consumers was 36.5% and prevalence rate of hypertensive kidney disease was noted among 3.6% of them. They were almost similarly exposed to this health problem compared to the same problem of non-consumers[ R.R.=1.13, C.I.(0.57, 2.24)]. It indicated that prevalence was independent of consumption of process food [ = 1.25, p –value= 0.724]. The smoker adults were 33.1% and 4.9% of them were suffering from both hypertension and kidney problem simultaneously. For them the risk of prevalence was 91% more as it was for non-smokers [ R.R.=1.91, C.I.( 0.98, 3.73)]. However , smoking habit was not significantly associated with the prevalence of hypertensive kidney disease [ = 3.667, p –value=0.056 ].

The percentage of obese adults was 30.2 and 9.7% of them were patients of hypertensive kidney disease. Their chance to be affected by this health problem was 16.80 times as it was for non-obese adults [ R.R.=16.80, C.I.( 3.88, 72.78)]. Level of obesity was significantly associated with prevalence of hypertensive kidney disease [ =  54.122, p –value=0.000]. Prevalence of diabetes was also significantly associated with prevalence of hypertensive kidney disease [ = 4.901, p –value= 0.027]. In the sample there were 67.0% diabetic patients and 4.2% of them were facing this health problem. For them the chance of prevalence was 2.75 times as it was for non-diabetic adults [ R.R.=2.75,C.I.(1.07, 7.06)]. Prevalence of hypertensive kidney was significantly associated with duration of diabetes and prevalence rate was in increasing trend with the increase in duration [ =94.881, p –value=0.000]. The percentage of diabetic patients suffering for 15 years and above was 7.1. Among this group the prevalence rate was observed 22.5% . For them  the chance of prevalence was 12.25 times compared to the chance of others [ R.R.= 12.25, C.I.(6.47, 23.21)].

The sample adults were classified into two groups. In one group there were 3.3percentage  hypertensive kidney patients. This group was significantly different from the remaining 96.7percentage adults of other group in respect of some socioeconomic characters. But all socioeconomic characters  were not similarly  responsible in discriminating two groups. The most responsible variable was identified by performing discriminant analysis. For the analysis the variables included were residence religion, gender, marital status, age, education, occupation, family income, family expenditure, utilization of time, physical work. Habit of taking process food, smoking habit, body mass index , prevalence of diabetes and duration of diabetes. Out of these variables, the impacts of  age, utilization of time, body mass index, prevalence of diabetes and duration of diabetes were significantly different for two group of adults. It was observed by F-test. The results of the tests and of discriminant analysis were presented in Table 3. The discriminant analysis was satisfactory as was observed by Chi-square test, where 

The analysis showed that the most responsible variable for discrimination of two groups of adults was duration of diabetes followed by age, body mass index, utilization of time, prevalence of diabetes, smoking habit, family expenditure, education, family income, etc. 

Table 3 : Results related to discriminant analysis

The damage of kidney due to chronic elevated blood pressure is termed as hypertensive kidney disease. The relationship between blood pressure and incident of kidney problem is evident in different studies in both home and abroad [ 17 -  19, 42 – 46 ]. The risk factors for this health problem  are older age, obesity,  prevalence of diabetes, physical inactivity, intake of fatty and high salt food, poorly controlled medium and high blood pressure and poor health management [ 18- 19, 31, 45 - 47]. Beside these variables, there may be some other variables enhancing the prevalence rate of hypertensive kidney disease.  The present paper was an attempt to identify some socioeconomic variables responsible for the prevalence of hypertension and kidney disease simultaneously in adults of Bangladesh. For this, 995 urban and rural adults of 18 years and above were investigated and related data were  collected and analysed.

The study of association between prevalence and socioeconomic variables  indicated that the prevalence of hypertensive kidney disease was independent of residence, religion, gender, marital status, education occupation, family income, and family expenditure. But the value of calculated risk ratio provided the information that non-Muslims, males, single adults, primary educated adults, agriculturists, and adults belonged to lowest economic condition had higher risk of prevalence. An inverse insignificant association between physical labour and prevalence was noted. Adults doing physical work had 45% more chance of prevalence of this health hazard. Age, utilization of time, obesity, prevalence of diabetes and duration diabetes were significantly associated with prevalence of hypertensive kidney disease. Discriminant analysis identified duration of diabetes as the most responsible variable for the prevalence. In order of weight of responsibility the other variables were age, body mass index, utilization of time, prevalence of diabetes, smoking habit, etc.  Elderly people of ages 50 years and above, persons involved in sedentary activity, obese adults,  diabetic adults,  adults suffering from diabetes for 15 years and above had 18.46 times, 2.50 times, 16.80 times, 2.75 times, and 12.25 times, respectively  risks of prevalence of the problem . 

The present paper provided analytical results to identify  some socioeconomic variables responsible for prevalence of hypertensive kidney disease in Bangladeshi adults. For the analysis, data were collected from 995 adults of 18 years and above residing in both urban and rural areas. Out of 995 adults 3.3% were hypertensive kidney patients. Higher prevalence rate, significant or insignificant,  corresponding to this rate was observed in  rural people ( 3.4), males (3.8%), non-Muslims ( 4.1),  single persons (4.3%), elderly people( 13.8%), primary educated adults ( 7.4%), farmers (4.8%), poorest people(4.8%), smokers ( 4.9%), process food consumers ( 3.6%), physically active adults (4.0%), adults involved in sedentary  activity (5.0%), obese people ( 9.7%), diabetic patients suffering for 15 years and above( 22.5%). However, except rural people and process food consumers, all other adults  suffering from the disease in higher rate were more exposed to this health hazard. The chance of prevalence of the disease was at least 50% more among elderly people, primary educated people, farmers, adults of lower economic conditions, smokers, adults involved in sedentary activity, obese adults ,and diabetic patients suffering for longer duration. The prevalence rate was in significantly increasing trend with the increase in both age and duration of diabetes. Finally, the hypertensive kidney patients was significantly discriminated from the remaining adults . The most responsible variable for the discrimination was duration of diabetes followed by age, body mass index, utilization of time, prevalence of diabetes, smoking habit, etc.

All the responsible variables except age were lifestyle factors. Some of these cannot be avoided due to socioeconomic upward mobility in the country. But the extent of risk of prevalence due to these variables can be reduced if people can regulate their lifestyle towards healthy life.  For this, they should be careful in

(i)         taking process and can food instead of home made healthy food,

(ii)        taking drinks and drugs,

(iii)       utilizing time towards health life outside the office hours/ normal working hours,

(iv)       adhering medical check up and treatment  after consulting a medical practitioner, 

(v)        maintaining blood sugar level and blood pressure level.