Magnitude and predictors of hospital admission, readmission, and length of stay among patients with type 2 diabetes at public hospitals of Eastern Ethiopia: a retrospective cohort study

Type 2 diabetes (T2D) is the most common type of diabetes, which is characterized by insulin resistance or scarce insulin activity due to a progressive loss of b-cell insulin secretion [1‐4]. Patients with diabetes usually experience comorbidities and complications more frequently than other patients [5]. Therefore, T2D patients have considerably higher rates of admission and longer in-hospital stay than the general population, which imposes a significant burden on healthcare systems [3, 6‐10].

Over a million diabetes were admitted to a hospital in England and Wales in 2017, during which one in six hospital beds were occupied by patients with diabetes and by 2030 it is predicted this will rise to one in four [8, 11].

The hospitalization of people with diabetes is commonly precipitated by various health-related conditions. The principal reasons for admission among diabetes are related to acute and chronic complications of diabetes [7, 10‐16]. Circulatory disorders such as congestive heart failure, coronary atherosclerosis, and acute myocardial infarction, were the main reasons for hospital admission [5]. Predictors of hospital admission among DM are older age, being less educated, low socioeconomic status, high alcohol use, longer diabetes mellitus (DM) duration, and disease severity [9, 14, 17].

Studies showed that high and middle income countries reported diabetes patients stayed in the hospital for an additional 1–6 days than other patients [6, 8, 11, 13, 18] and longer in low income countries [7, 12, 19]. In Ethiopia, the median duration of hospital stay among DM patients was 9 days (interquartile range of 14 days) ranged from 1 to 88 days [15]. Poor health care service processes, occurrence of co–morbidity, and high rate of complications in diabetes are responsible for these excess lengths of stay in DM patients [5, 12, 13, 15, 20]. Beside these figures there is little information about the burden of hospitalization of diabetic patients in Eastern Ethiopia. In addition, it is valuable to identify the main causes of hospital admission and duration of hospitalization among DM. Therefore, this study aimed to assess the magnitude and predictors of hospital admission, readmission rates, and length of hospital stay among type 2 diabetes in public hospitals of Harar, Eastern Ethiopia.

This study was designed to assess predictors of hospital admission, readmission, and length of hospital stay among T2D patients on follow up at hospitals of Harari regional state. The five-year incidence of hospital admission was 9.85 per 1000 people per observation time. This result was lower than studies conducted in the United Kingdom (UK) [3], USA [36, 37], and New Zealand [18]. However, our finding was higher than the report from the study conducted in other Sub Saharan Africa like Uganda (4.2% )[38], and Nigeria (10%) [39]. The difference might be due to the difference in health service coverage, health seeking behavior of patients, and admission guidelines/protocols between the countries.

Being a rural resident may increase the probability of hospital admission by more than three times compared to the urban residence. The possible explanation for this finding might be due to the poor diabetic control among T2D from rura l[40, 41]. Similarly, T2D patients from rural areas have low socioeconomic status and opportunity to medical care which make them more prone to hospital admission [42]. The findings of this study, therefore, raise potentially important quality-of-care concerns. Contrary to this finding, the pooled analysis from a study conducted in Poland reported the urban patients have higher probability of hospital admissio n[43]. The difference might be raised from the difference in the study population and the statistical model used. The former study was conducted among patients older than 45 years and compared with patients with malignancy.

Compared to physically active patients, the probability of hospital admission and readmission among patients who live inactive lifestyle were increased by 88 and 71%, respectively. This finding was in line with the report from Australia [44]. The recommended physical activity for T2D is at least 150 min/week of moderate to vigorous aerobic exercise spread out to at least 3 days per week, with no more than two consecutive days between bouts of aerobic activity [45‐47]. Otherwise, inactive patients are more prone to insulin resistance, obesity, and comorbidities than diabetes patients living an active life style. As a result, the frequent hospitalization due to those comorbidities and diabetic complications could be higher among patients with inactive life.

Drinking alcohol increases the hazard of hospital admission by 2.3 times higher than patients who did not drink alcohol. Behavioral risk factors in general and alcohol drinking in specific have a significant role in poor diabetic control [6, 48]. Previous studies also indicated that drinkers had the greatest compliance with each self-care behavior, and dehydration induced hypoglycemia [48‐50]. Alcohol can cause the accumulation of certain acids in the blood that may result in disturbances in fat metabolism, nerve damage, and eye disease [49].

Having at least one diagnosed chronic diabetic complication increases the probability of hospital admission by about 20% than those who did not have a history of diagnosed diabetic complications. Similarly, having at least three medical histories of comorbidities increased the likelihood of hospital admission by more than four times compared to those who had no diagnosed comorbidities. The finding was comparable with studies conducted in USA [51, 52], UK [3], Australia [9], and Korea [53]. Evidence also indicate that hospital morbidity results from chronic microvascular or microvascular complications [54]. If early screening and preventive activities are implemented, asymptomatic identification of comorbidities and commence treatment are not commenced patients could experience frequent hospitalization [53‐56].

As the duration of diabetes increases by one year, the probability of hospital readmission was increased by 14%. The result is similar to the previous reports in Australia [6, 9], and the USA [24]. Diabetes complications and comorbidities are increasing with age and diabetes duration [57‐59]. Hence, the frequent hospital admission might correlate with diabetes duration due to the comorbidities and diabetes complications over a long period.

The association between sex and admission, and log rank result for readmission was not significant in univariate but significant in multivariate analyses. The reason of sex be significant when more predictor variables are entered into the model is explained the increment of power and loose of significance. The residual variability decreases in multiple regression since we are comparing the slope to a null distribution that is estimated using the residual variability. Meanwhile the residual degrees of freedom also decrease, so it’s possible that power could be increased in robust model [60].

The hazard of first admission among female T2D was decreased by 29%. However, being female increases the risk of readmission by 26% and LOS by 12% compared to males. This report was contrary to the previous study conducted in Australia [9], USA [36]. A study conducted in India suggested that women had less self-efficiency related to their diabetic self-care and higher chances of bad dietary practices than men [61]. Another study also revealed that females had significantly higher annual rates of symptomatic, glucose-confirmed symptomatic, and severe hypoglycemia than males [62]. All these factors might be increasing the probability of frequent admission and LOS among female patients.

The likelihood of readmission was 2.3 times higher among patients with BMI 30 kg/m² or more compared to patients having BMI less than 25 kg/m². It is consistent with the report of studies from New Zealand [18] and the USA [63]. Previous study also reported that unfavorable diabetes outcome is higher among obese individuals [64].

As the blood glucose level was increased by 10 dl/ml, the risk of admission, readmission, and LOS was slightly increased. This finding was in line with previous studies [65‐69]. Uncontrolled blood glucose is the foundation of most diabetic complications and comorbidities among T2D patients [70]. Despite the marker of poor clinical outcome is shown as hyperglycemia [71], it is not proven whether admission hyperglycemia is a risk factor itself, a marker of severity of illness, a marker of poor patient compliance with treatment, or a sign of less rigorous medical care.

The LOS among patients having a history of insulin administration on the admission time was increased by more than three times compared to those who had no history of insulin administration. This finding is in agreement with the report of previous studies [53, 72, 73]. This finding might be related to the side effects of insulin (i.e., hypoglycemia). Hence, cautious monitoring of signs of side effects of insulin administration is important. Insulin might be administered to T2D patients if they have uncontrolled blood glucose levels and DM complications during admission. However, a study conducted among hospitalized elderly patients showed there was no difference in LOS by their insulin administration status [74]. The difference might be due to the difference in the study population as the former study used elderly hospitalized patients.

The combination of metformin and glibenclamide treatment showed a decrement in the number of readmissions and LOS by 46 and 65% respectively. Reports from randomized control trials showed that a combination of treatment is more effective than a single drug in improving glycemic control in type 2 diabetes and reduction of the dosage of each drug [75, 76].

Findings from this study should be interpreted in light of the following limitations. This study neither establish the causality nor representativeness to the whole country as it encountered the problem of small sample size for readmission and LOS, and the limitations of data completeness/accuracy common to most retrospective studies. Furthermore, important determinants like diabetes self-care (diet modification, life style, exercise, etc.) and treatment during hospitalization, organ function tests, and HgA1 were lacked from the chart of the patients. Moreover, we were unable to control for some risk factors, such as laboratory values and hospital acquired complications as these factors were not recorded. In addition to these, we could not get information on medications like anti-hypertensives, fibrates, and statins.

Three out of ten T2D patients had a history of admission and half of those patients with a history of admission were readmitted again within five years. Multiple and complex factors were contributing for high diabetes admission and readmission rates as well as for longer duration in hospital among T2D patients in Harari regional state. Hospital admission was determined by inactive life style, place of residence, presence of a history of comorbidities, and chronic complications while readmission was significantly increased with duration of disease, inactive lifestyle, being female, having a larger BMI, and decreased by having a normal average glucose level. The length of hospital stay was longer for those females, patients with the history of insulin administration, and patients with elevated blood glucose levels. Therefore, health care providers should give due emphasis to diabetes patients with risk factors for admission, readmission, and longer duration in hospital. Effective primary preventive strategies should be implemented at diabetes follow up clinic to reduce the hospitalizations and longer hospital stays among diabetic patients. Health professionals should provide continuous health education for all T2D patients at follow up clinic about the risk factors of hospitalization. All hospitals who provide diabetes care should implement standardized diabetes management guidelines and treatment protocols to avoid unnecessary hospitalization and hospital stay.