In-Patient Morbidity and Mortality Patterns among Patients with Diabetes in Southwest Nigeria: A Multicenter Prospective Study

Abstract

Background: 

Diabetes is a disease of public concern with increasing hospital admissions and mortality in developing countries. Hence, we aimed to determine the patterns of in-hospital morbidity and mortality in patients admitted for diabetes.

Methods: 

A prospective multicenter analysis of the causes of hospital admission and death among patients with type 2 diabetes who were admitted from diabetic clinic and emergency units over a 3-month period in selected tertiary hospitals in southwest, Nigeria was conducted. Data analysis was performed using the SPSS version 21.0.

Results: 

A total of 341 patients with diabetes were admitted with a mean age of 59.6 ± 15.6 years and overall mortality of 14 deaths (4.4%). Almost three-fifths (59.5%) were previously known patients with diabetes with a mean duration of 52.44 ± 30.02 months. Two hundred and thirty-one (70.9%) patients were admitted through the emergency units and others through outpatient clinics. The duration of hospital stay ranged from 1 to 135 days, with a mean duration of 24.5 ± 14.7 days. The diabetes-related indications for admission were hyperglycemic crisis (diabetes ketoacidosis [DKA] and hyperglycemic hyperosmolar state [HHS]) (59.8%), diabetic foot ulcer [DFU], (11.7%), hypoglycemia (7.6%), and infections (7.3%). Among the diabetes-related diagnoses, 100%, 77.8%, 50.0%, 41.7%, and 28.3% of patients with chronic kidney disease, stroke, DFU, DKA, and HHS respectively stayed longer than 10 days on admission.

Conclusion: 

Diabetes still contributes high cause of morbidity in our hospitals but with a reduced mortality compared to previously reported figure. Hence, continued emphasis on early diagnosis with improvements in diabetes care will help to improve diabetes outcomes.

INTRODUCTION

Globally, an estimated 537 million people live with diabetes mellitus (DM) in 2021, causing at least USD 966 billion in health care expenditures,^[1] and 80% of these people are living in low-and middle-income countries (LMICs) including Nigeria.^[1] Approximately 6.7 million individuals die of diabetes and nearly half of these deaths occur in people under the age of 60.^[1] In Nigeria, the national prevalence of DM is 2.2%^[2] with a higher prevalence in urban communities than in the rural communities. However, studies from different parts of the country have reported rates between 1% and 8%.^[3–7] In a recent systematic review on the burden of diabetes in Nigeria, Uloko et al. reported an overall prevalence of 5.77% with variation from one geopolitical zone to another.^[8]

Diabetes is associated with increased morbidity and mortality, especially in mainly developing countries as a results of its acute complications particularly diabetes ketoacidosis (DKA), hyperglycemic hyperosmolar state (HHS), and hypoglycemia. The mortality from these acute metabolic complications in Nigeria ranges from 10% to 15%.^[9,10] In the United States, diabetic ketoacidosis (DKA) accounts for more than 110,000 hospitalizations annually, with mortality ranging from 2% to 10%.^[10–13] Hyperglycemic hyperosmolar state (HHS) is much less common but confers a much greater mortality.^[11] In contrast to LMICs, stroke and acute myocardial infarction are the main causes of mortality in patients with diabetes in countries with high economic income.

The optimal approach to determine mortality rates among people with diabetes is to use a prospective cohort design where the diagnosis of diabetes is established at admission and patients are followed until outcomes are determined (discharged home, discharging against medical advice [DAMA], or death). The main objective of this study was to document clinical presentation and outcome of patients admitted with DM to devise means of reducing morbidity, admission rates, and mortality in these patients.

METHODS

This was a prospective study conducted in five tertiary health institutions located in the Southwest Nigeria. The southwest comprises six states which are largely homogenous as majority of the people are of Yoruba extraction. The selected hospitals were LAUTECH Teaching Hospital, Ogbomoso, Bowen University Teaching Hospital, Ogbomoso, Federal Teaching Hospital, Ido-Ekiti, Federal Medical Centre, Owo, University of Medical Sciences Teaching Hospital Ondo and General Hospital, Odan, Lagos. The study participants were patients, aged at least 40 years, admitted with diagnosis of DM (type 2 diabetes) as established or confirmed by a physician with or without comorbidities. The study period was between March and July, 2019. The information obtained from each patient included personal data, diagnosis, type of diabetes, duration of diabetes (if previously diagnosed), previous hospital admission due to diabetes, duration of illness before presentation, mode of treatment of diabetes, duration of stay in the hospital and outcome. Pregnant women and patients admitted for diagnostic or therapeutic procedures such as kidney biopsy, peritoneal dialysis catheter placement, or those that declined consent were excluded

Statistical analysis

Data were analyzed using The Statistical Package for Social Sciences, Inc, Chicago, IL, USA (SPSS version 20.0). Descriptive statistics (frequency distribution, percentage, mean, and standard deviation) was used to summarize the characteristics of the study population. The clinical findings and laboratory data obtained were recorded at the time of hospital admission. The association between in-hospital mortality rate and sociodemographic, clinical variables and causes of hospitalization were assessed using regression. Statistical significance was set at P < 0.05.

Ethical approval

The study was reviewed and approved by the Institutional Ethical Committees of all the participating centers. Oral informed consent was also obtained from patients and/or next-of-kin when patients were too weak to give consent.

Variables definition

The outcome of interest was time until event defined as the time in days, elapsed from admission until the patient was discharged by medical indication, voluntarily DAMA or died during hospitalization. The diagnosis was as determined by the admitting physician either at the outpatients clinic or accident/emergency unit at the moment of hospital admission. Causes of hospitalization were noted as infections (urinary, respiratory, subcutaneous tissue, or diabetic foot), metabolic disorders ([diabetic ketoacidosis, and hyperosmolar state], and hypoglycemia), stroke, diabetic foot ulcers (DFUs), chronic kidney disease (CKD).

Definition of causes of hospitalization assessed in the study.

RESULTS

A total of 341 patients were admitted to the medical wards in all the participating hospitals during the study period, out of which, 198 (58.1%) were female. The mean age of the patients was 59 ± 14.2 years (range, 40–91 years) [Table 1].

Table 1: Sociodemographic characteristics of the study participants

Almost three-fifth (59.5%) were previously known patients with diabetes and the mean duration of diabetes among them was 52.44 ± 30.02 months and 64.9% were either overweight or obese. Two hundred and thirty-one (70.9%) patients were admitted through the emergency units and others through outpatient clinics. Of those who were on treatment for diabetes before admission, 149 (70.6%) and 31 (14.7%) were on oral hypoglycemic agents and insulin respectively and 63/223 (28.3%) had glycated hemoglobin (HbA1c) of 7% or less. Eighty-one (40.5%) patients had a duration of diabetes between 5 and 10 years before admission and only 45/181 (24.9%) had diabetes-related admission within the last 12 months. Among the study participants, 158 (52.1%) had duration of illness prior to admission for <7 days and 57 (18.8%) had illness for 15 or more days before presentation in the hospital [Table 2].

Table 2: Clinical characteristics of the study participants

The diabetes-related indications for admission are shown in [Table 3]. Hyperglycemic crisis (DKA and HHS) accounted for (59.8%), DFU (11.7%), hypoglycemia (7.6%) and infections (7.3%). Although only 2.5% of the patients were admitted for CKD, 23.0% had serum creatinine greater than 120 mmol/L, indicating possible nephropathy. Other indications were tuberculosis, cancers, diabetic hand syndrome, etc., grouped together as others and these accounted for 8.5% of the admissions. In contrast, 139/290 (37.6%) stayed for >10 days on admission and only 42/290 (14.5%) stayed for <5 days on hospital admission. Among the diabetes-related diagnoses, 100%, 77.8%, 50.0%, 41.7%, and 28.3% of patients with CKD, stroke, DFU, DKA, and HHS respectively stayed longer than 10 days on admission. The duration of hospital stay ranged from 1 to 135 days, with a mean, mode and median (interquartile range) duration of hospital stay of 24.5 ± 14.7 days, 9 and 7 days, respectively.

Table 3: Diabetes-related diagnosis and duration of hospital stay

As shown in Table 4, 3.2%, 10.0%, 11.6% and 12.0% of those admitted with hyperglycemic crisis, DFU, stroke, and infections during hospital admission died giving an overall mortality rate of 4.4%. Those who discharged themselves against medical advice (DAMA) comprised 25% of those with CKD and DKA, 20% with stroke, 10% with infections, and 7.5% of those with HHS. DAMA among our patients occurred majorly because of lack of funds for surgery (amputations/debridement), continued treatment and refusal for surgical interventions. Also some DAMA because of their wrong belief that their sickness especially those with DFU were due to “spiritual attack” which in their belief does not respond to orthodox mode of management.

Table 4: Treatment outcome according to diagnosis

As shown in Table 5, none of the demographic and type 2 diabetes-related variables were associated with mortality. Also, when the sum of causes of admission was assessed, an increase in the number of conditions (co-morbidities) was associated with a greater risk of mortality.

Table 5: Determinants of treatment outcome

DISCUSSION

This study is one of the few prospective studies evaluating the pattern of hospital admission as potential risk factors for in-hospital mortality among patients with diabetes in Nigeria, as most of the in-hospital mortality studies are retrospective in nature.^[13–16] Study has shown that the risk of death as well as pattern of mortality among diabetics varied according to the cause of admission, location, and race. For example, Caucasians with diabetes were more likely to die from coronary artery disease compared to Africans who are at higher risk of dying from hyperglycemic crisis, infections, renal and heart failures.^[17] In Nigeria, studies have shown a diabetes-related mortality of between 3.4 and 32.7% with hyperglycemic emergencies, infections, stroke, and DFUs as leading causes.^[13–15] Comparing with our results, in-hospital mortality of 4.4% was significantly lower, but the pattern of morbidity and causes of death remained unchanged over time. This mortality rate is also much lower than mortality rates reported for sub-Saharan African countries by IDF.^[1]

In this study, hyperglycemic crisis (HHS and DKA), and DFUs were the main causes of in-hospital admission, with hyperglycemic emergencies (HHS and DKA) accounting for approximately three-fifth (59.8%) of total admissions. Similar to our findings, most studies reported that hyperglycemic emergencies, accounted for the majority of diabetes admissions.^[14,18–24] However, these findings differ from findings by Eregie et al.,^[25] who reported cerebrovascular disease and DFUs as the commonest causes of hospital admission.

The acute complications of diabetes, mainly HHS, DKA, and hypoglycemia, which are frequent indications of hospital emergencies in Nigeria, and associated with high mortality has been attributed to high numbers of undiagnosed cases and low treatment rates which make patients with diabetes present with a high prevalence of complications.^[26,27] It is common for people to be diagnosed with diabetes, with or without complications for the first time in the emergency room^[19,28] Recent reports within Nigeria show that undiagnosed cases of diabetes account for about 40% of the diabetes burden in the country, causing over 50 000 deaths from diabetes and its complications in the country.^[29] Personal health costs from diabetes, mostly out of pocket (>70%), may also affect hospital visits and medication use. The lack of a fully functional and equitable national health insurance scheme^[16] means many people with diabetes prefer to stay at home, visit substandard facilities or patronize traditional herbal healers, due to the high cost of treatment and medications,^[26] only to present at an advanced stage of the disease to standard health facilities with widespread complications.

In our study, the mortality rate among patients with hyperglycemic emergencies was 3.2% and this occurred among patients with HHS, none in those with DKA. This mortality is much lower than 10.2% reported by Unadike et al.^[15] and slightly lower than the accepted mortality rate of 5%–10%.^[17] HHS, a common complication of type 2 diabetes usually occur in the elderly and often present with concurrent comorbidities. The improvement in the mortality rate in our study may be due to availability of endocrinologists who deployed their expertise during the prospective study. Whereas lack of access and high cost of insulin, delays in seeking medical attention, misdiagnosis, and poor diabetic may all are among the contributory factors to this attendant high mortality, availability of diabetes experts will help improve prognosis during diabetes-related admission especially if due to hyperglycemic crisis.

Although infections still increase in-hospital mortality among our diabetic patients, other causes are potential risk factors especially DFUs, stroke, and chronic kidney disease. As countries, states, and geopolitical zones are at different levels of development, including availability of equipment and human resource, hence, the causes of death can vary according to the setting accessed. Therefore, there is need to understand the patterns and characteristics associated with the risk of death in each locality of the country periodically.

Diabetes foot ulcer was the second-most common cause of hospital admission and accounted for 11.9% of our diabetes admission. However, in a study carried out at Ido-Ekiti, Nigeria on admission pattern of diabetes-related diseases, Ajayi et al.,^[13] reported diabetes foot ulcer was the commonest reason for hospitalization. DFS has been reported to be the cause in 4.2%–19% by other workers.^{[19,21,22,30]} The mortality rate among those with DFS in this study was 10.0%. This rate is significant considering the enormous morbidity and mortality associated with the disease.^[31] DFU, which is majorly preventable, continues to cause significant morbidity among patients with diabetes in Nigeria. It is hoped that proper, regular and aggressive patient education will halt this undesirable trend in future.

The percentage contribution of hypoglycemia (7.6%) to diabetes admission is higher compared to other studies,^[19,22] although not associated with mortality in this study. Olamoyegun et al.^[32] had reported high incidence of hypoglycemia among type 2 diabetes in Nigeria but with low mortality. However, Chijioke et al.^[14] in Ilorin, North Central, Nigeria had reported hypoglycemia, stroke and DFU to have accounted for the highest causes of mortality in their study. In addition, Unadike et al.,^[15] had reported hypoglycemia to have accounted for 3.0% mortality in diabetes-related admission in Uyo, Nigeria. Hence, intensification in diabetes education at the outpatient clinic will help as a preventive measure to hypoglycemia occurrence.

It was observed that DFUs required the most prolonged duration of hospital stay in this study (36.5 ± 28.4 days) and least in hypoglycemia (4.5 ± 3.7) days. In a study by Ajayi et al.^[13] the mean duration of diabetes-related hospital stay was also the longest in patients admitted for DFU. Similar finding was reported in studies from an urban teaching hospital in the Lagos metropolis of Nigeria.^[27]

Approximately a quarter of hospital-admitted patients met recommended optimal HbA1c levels of <7.0%. Several studies in different settings have reported few patients with diabetes achieving good glycemic control rates.^[32–34] Adequate glycemic control has been shown to reduce the risk of developing complications, particularly microvascular complications.^[35] The study also showed that a sizeable number of admitted patients DAMA. The commonest reasons for these were inability to fund medical treatment (financial constraints) and refusal to accept mode of treatment, for example, amputation for those with DFUs. The roles of diabetes advocacy organizations, like Diabetes Association of Nigeria leading the fight to stop diabetes and its deadly consequences and to improve the lives of those affected by diabetes is very important. These efforts will help to improve identification, prevention, and management of T2DM leading to subsequent reduction in morbidity, mortality, and costs.

Limitations and strengths

The strengths of this study include its prospective nature, its being a multicenter study, proper assessment conducted by a consultant endocrinologist to verify and confirm the diagnosis and the reason of hospitalization, and the use of tertiary centers in the Southwest, Nigeria to perform the study. This study, however, has some limitations. First, the participating centers all have at least a consultant endocrinologist who is an expert in the management of diabetes. Hence the findings in this study especially the minimal mortality may be difficult to generalize to most of the country and beyond where such specialists are not readily available

CONCLUSION

This study showed that hyperglycemic crisis, DFU, hypoglycemia, and infections are major causes of morbidity frequently leading to hospitalization and infections, strokes, DFUs and less of hyperglycemic crisis are frequent causes of mortality. Encouraging patients to attend outpatient clinics, national diabetic programs, and the increased use of diabetes specialists would improve the quality and outcome of diabetes management by improving in the overall mortality rate among hospitalized patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.