The Pattern of Admission, Clinical Characteristics, and Outcomes Among Patients Admitted to the Intensive Care Unit of a Tertiary Hospital in Tanzania: A 5-Year Retrospective Review

Introduction

The Intensive Care Unit (ICU) is a specialized unit serving patients with severe and life-threatening illnesses requiring intense and sophisticated treatment to maintain normal physiological function.¹ Mortality in ICUs remains high even with the utility of the latest and most costly equipment. ICU mortality in many African countries^2–9 both in the public and private sector, is markedly high and exceeds by multiple folds when compared to ICUs in High-Income Countries (HICs).^1,7,10 Documented ICU mortality rates exceeds; 25% in Ethiopia,⁵ 35% in Tanzania^2,3 and Uganda⁹ and approaches 60% in Kenya.⁶ Over the past two decades, ICU care in the developed world has noticeably improved in technologies and the quality of care it can provide, resulting in an improved survival rate.¹⁰ These trends have not been consistently observed in developing and resource-limited settings, including Sub-Saharan Africa (SSA).⁶ The development of Critical care in SSA, especially in the public sector, has been a challenge,¹¹ largely due to a shortage of resources and a lack of sufficiently skilled personnel compounded by poor health-seeking behaviors by the public.

Despite the COVID-19 pandemic placing SSA in an unchartered region and calling upon urgent development of ICU care, there remain limitations in scaling up appropriate critical care in the region.¹² With the African continent currently experiencing a double burden of rising rates of Non-Communicable diseases (NCD) in the background battle of combating infectious diseases and an aging population, the demand for critical care is more than ever before.¹³ ICU care in Tanzania has been poorly described, with large variations reported in the public and private sectors.^2–4 Most ICUs in Tanzania are developed in tertiary and private hospitals in urban areas, not serving most of the population living in rural areas.¹⁴ Given the recent initiatives of the Tanzanian government post-COVID-19 pandemic to increase the critical care capacity in the country, this analysis is timely to serve as an information platform for developing healthcare policies in the region. No study to date has assessed ICU outcomes in well-resourced settings in Tanzania, comparable to many tertiary-level hospitals in High-Income Countries (HIC).

This study aimed to identify clinical characteristics and elaborate on risk factors associated with ICU mortality. The study was carried out amongst the ICU patients who were admitted at the Aga Khan Hospital located in Dar-es-Salaam, Tanzania. This study will add to the prevailing limited critical care literature from this region.

Methodology

Study Design

We conducted a retrospective cross-sectional study that reviewed records of medical patients¹⁵ admitted to the ICU of the Aga Khan Hospital Dar-es-Salaam, Tanzania, from 1st October 2018 to 31st April 2023.

Study Setting

The Aga Khan Hospital is Tanzania’s first and only Joint Commission International (JCI) accredited hospital. It provides level three care to critically ill patients. It can treat 15 patients in its ICU. The 15-bed ICU is divided into 7 beds for general critically ill patients, 4 reserved for pediatric patients, and 4 for cardiac patients. The ICU of the Aga Khan Hospital is able to provide level III services to critically ill patients.¹ The Unit is capable of providing invasive and non- invasive monitoring of vitals. The organization of the ICU utilizes an open model system run by a multidisciplinary team comprising of the physician of primary specialty, the nutritionist, the physiotherapist and led by a full-time critical care specialist. The nurse-to-patient ratio is 1:1. Resident doctors in the internal medicine department from Aga Khan University actively participate in the care of medically admitted patients.

Study Population

All consecutive patients aged 18 years and above meeting the institution’s strict admitting criteria admitted with a medical diagnosis as well as having a final ICU outcome were studied. The study excluded patients admitted for observation, those without a complete set of inpatient data, and those suspected or diagnosed with COVID-19 disease.

Data Collection

The primary investigator identified the patients from the department’s admission registry, and patient files were retrieved from the institutional medical records. Medical doctors working in the ICU volunteered as research assistants to collect all the necessary data, both in paper-based and electronic formats. Data collected included the following: basic demographic information, source of admission (transferred from ward, emergency), underlying comorbid illness, available laboratory data, admitting diagnosis, organ support, interventions, and relevant admitting section. In cases with more than one critical care diagnosis, entity that was associated with worst prognosis was chosen as the lead diagnosis. The collected data was incorporated into a Microsoft Excel 2010 (Redmond, WA, USA). The data collected was randomly rechecked by the primary investigator to ensure that it was accurate and complete.

Data Analysis

Proportions and frequencies were used to represent Categorical variables. They were compared with the use of chi-squared or Fisher’s exact tests. Means and medians were utilized to represent continuous variables and the comparison was done with the aid of Mann Whitney tests or independent t-tests. Statistical significance was set at P- value <0.05. Any variable demonstrating statistical or clinical significance in explaining ICU mortality was considered in the multivariate model. We used p-values, odds ratio (95% confidence interval) and, binary logistic regression to present determinants of ICU mortality. IBM Statistical Package for Social Sciences version 23.0 was used to perform statistical analysis.

Ethical Consideration

Aga Khan University Ethical Research Committee (AKU ERC) at provided ethical approval for the research (AKU/2023/012/fb/09/013).

Results

A total of 717 patients were included in the study out of which (n=128,17.9%) died and (n= 589,82.1%) survived. Table 1 below illustrates the general and clinical characteristics of the study population and provides a comparison between Survivors and non-survivors. Our cohort was predominately African (n=471,65.7%) with the majority being male (n=472, 65.8%) having a median age of 58 years (IQR 45–71.0). The majority of ICU admission were admitted from the emergency department (n=643, 92.8%). When survivors and non -survivors were compared, the higher median age of 65.5 years (IQR 51.8–75.2), greater BMI 27.2 kg/m²(IQR 24.1–31.1) and prolonged length of stay of 4 days (IQR 2.0–8.2) was noted amongst the non- survivors as seen in Table 1 below.

Table 1 Demographic characteristics of the study Population

The majority of the cohort suffered from an infectious (n= 175,24.4%), neurology (n=111,15.5%), and cardiology-related- condition (n=110,15.4%). The highest mortality was noted amongst those admitted with an infectious disease condition (n=40, 31.2%), as seen in Table 2 below.

Table 2 Admitting Category of the Study Population

Figure 1 below illustrates the most common ICU diagnosis in our cohort. The mortality was highest in patients with septic shock (29.3%).

Figure 1 Most common ICU diagnosis among medically admitted patients. Abbreviations: AHF, Acute Heart Failure; DKA, Diabetic Ketoacidosis; UGIB, Upper Gastrointestinal bleeding; AKI, Acute Kidney Injury; CVA, Cerebrovascular accident; COPD, Chronic Obstructive pulmonary disease; PE, Pulmonary Embolism; ADS, Acute Respiratory Distress Syndrome.

Table 3 below illustrates underlying comorbid illness in our cohort and provides a comparison between survivors and non-survivors. Multiple comorbidities, if present, were reported. The most common comorbid condition was hypertension (n= 315,43.9%) and Diabetes Mellitus (n= 220,30.7%). The highest mortality was amongst those with Chronic Kidney Disease (CKD) (n=28,21.9%), and the Lowest survival rate was among those with more than three comorbid conditions (n=22,3.7%).

Table 3 Underlying Comorbid Illness in Our Cohort

Table 4 below illustrates the type of organ support patients received within the first hour of ICU admission. Of the 717 patients (n=420, 59.3%) did not receive any organ support within the first hour of ICU admission. The highest mortality was noted amongst those who received inotropic support within the first hour of ICU admission (n= 72.56.2%). The highest survival rate was also noted amongst those who required no organ support in the first hour of ICU admission (n- 397,68.2%).

Table 4 Type of Organ Support Within the First Hour of ICU Admission

Figure 2 below illustrates the values of C-reactive protein (CRP) at the time of admission. The mean CRP value was 88.4 mg/L (±108.9). A higher CRP value was seen among the non - survivors 115 mg/L (±123.8) when compared with the survivors 82 mg/L (±107)

Figure 2 Admitting CRP values between survivors and non - survivors. P-value 0.005 (Welch Two Sample t-test).

Advanced age (OR 1.02, 95% CI 1.00–1.04), having more than three underlying comorbidities (OR 2.50, 95% CI 1.96–6.60), use of inotropic support (OR 3.58, 95% CI 1.89–6.80) and mechanical ventilation (OR 9.11, 95% CI 4.72–18.11) within the first hour were associated with increased mortality as seen in Table 5 below.

Table 5 Factors Associated with ICU Mortality

Discussion

Per our literature search, studies on medical admissions to the ICU over a five years in Tanzania are scarce. The ICU mortality at the Aga Khan Hospital Dar es Salaam was 17.9%. In our study, mortality was the highest in patients with septic shock. Previous findings from the Aga Khan Hospital Dar-es-salaam that looked into the performance of predictive scoring models reported similar findings.⁴ Our study results depict a very low ICU mortality rate when compared to similar studies done in Tanzania^2,3 and other countries in Sub-Saharan Africa.^{5–9,16–18} The discrepancy can be chiefly attributed to the level of care that the hospital provides, which is comparable in various ways to facilities in High-Income Countries (HICs). The ICU of the Aga Khan Hospital Dar-es-Salaam is a well-structured and resourceful unit run by a multidisciplinary team able to provide level III care¹ to all its admitted patients. Additionally, the Aga Khan Hospital Dar es Salaam is a teaching hospital of the Aga Khan University. The majority of the healthcare workers at the hospital are linked with academic activities at the university. Numerous studies have reported low ICU mortality and better outcomes in major teaching hospitals when compared to non-teaching hospitals.^19,20 This is purely centered on constant and evidence-based updated practice. Our study did not report on the acuity of patients on admission, which may differ from one setting to the other, thus making it difficult to precisely compare mortality rates. Our in-ICU mortality rates are similar when compared to developed countries in Northern America and Europe^7,21–23 as well as in some parts of Asia.^24,25

Globally, septic shock is the leading cause of death among adults admitted to the ICU and the results of our study also reflected a similar trend.²⁶ Various systemic reviews and meta-analyses have reported an average in-ICU mortality rate between 30–40%.^27–29 Regional disparities exist, with higher mortality rates reported in low and Low Middle-Income Countries (LMICs).³⁰ Despite various advances in medical care and life-saving interventions, the Septic shock mortality paradox can be explained by its rapid progression,³¹ delayed health-seeking behavior,³² aging,³³ comorbidities,³¹ resistant pathogens³⁴ and its heterogeneous approach.³⁵ The in-ICU mortality rate among patients with septic shock at our center was approximately 30%, in line with global³¹ and previously conducted studies at our center⁴ but much lower when compared to studies done in other parts of Africa.^2,3,6,36,37 The infectious disease section of the hospital has made great efforts in setting up a well-equipped laboratory and a comprehensive antibiotic stewardship program able to deliver time-sensitive results and combat antimicrobial resistance. Nonetheless, this is insufficient and might not be applicable in the public sector due to resource limitations. Thus, the sole weapon that cuts across every community is advocating preventive measures such as good hygiene practices, early and prompt referrals, better control of underlying comorbid illness, and access to age-matched vaccinations. Despite the sepsis syndrome having a greater impact on short-term mortality, survivors also suffer from long-term sequelae affecting cognitive and organ function as well as increased risk of rehospitalization.³⁸ The scope of the current study was beyond long-term follow-up, but our observations are well within published reports.

The study identified increasing age, comorbidities (more than three), and the need for organ support as key factors associated with ICU mortality. Increasing age has been well-studied among various ICU cohorts and found to be an independent risk factor.³⁹ Several studies have reported a stepwise increase in ICU mortality among individuals after the age of 60 years.⁴⁰ Increased age is associated with various underlying comorbidities in addition to their principal diagnosis mitigating the multimorbidity state, frailty, and polypharmacy, posing a challenge even prior admission. The number of older patients requiring ICU admission is expected to increase given the aging global population and confers uncertainty of its short- and long-term benefits.⁴¹ Thus, this study advocates the improvement of geriatric medicine and palliative care, especially in resource-limited settings, as well as the use of illness-predictive scoring models in clinical practice to scientifically predict outcomes. More than one-third of patients who succumbed to death in the ICU had more than three underlying comorbid conditions. Our study did not specifically identify a particular comorbid condition related to ICU mortality, but NCD⁴² has been shown to influence the course of admission and negatively impact outcomes. Thus, admitting physicians should collectively identify high-risk individuals and guide discussion about realistic outcomes prior to admission.

The study also identified Inotropes and mechanical ventilation to be key factors associated with in-ICU mortality. This can be justified by the acuity of the patients requiring organ support for respiratory failure and hemodynamic compromise. Several studies have reported similar findings.^43–45 These findings do not underscore the importance of these interventions but prove the existence of the double-edged sword. Inotropes induce myocardial ischemia and arrhythmias as well as render critically ill patients to central line-associated bloodstream infection (CLABSI). Due to the study’s retrospective nature, we could not elucidate the specific inotropic agent associated with increased mortality. Nevertheless, few reports have indicated specific agent, dose, and time-dependent associations.⁴⁶ Despite mechanical ventilation being considered a lifesaving and beneficial intervention, it can also directly predispose an individual to increased risk of death through ventilator-associated complications, lung injury, and the development of nosocomial infection. Hence, ICU teams need to continuously adapt and refine approaches to improve outcomes amongst mechanically ventilated patients and cautiously monitor critically ill patients on organ support.

Limitations of the Study

Despite this being one of the largest studies to be conducted among critically admitted medical patients in Tanzania. This study had multiple limitations. Firstly, due to its retrospective nature, only limited charts and medical files were retrieved, and not all necessary variables were studied, especially physiological and laboratory parameters. Multiple diagnoses in a patient might have skewed the validity of the exact mortality rates of a specific condition. The Single-center nature, more so in the private- sector, limits the results generalizability.

Conclusion

In summary, this is the first paper in Tanzania to review 5-year data of medically admitted patients to the ICU of a private tertiary hospital. The in-ICU mortality was reported to be 17.9%, much lower than another sub-Saharan cohort. Patients admitted with septic shock had the highest in ICU mortality. The elderly with multiple comorbidities requiring organ support would likely not survive hospital discharge. A large multi-center national prospective study will highlight the true burden of critical care illness in Tanzania.

Future Direction

It is expected the burden of critical care will increase in SSA. Consequently, capacity building, infrastructure enhancement, telemedicine, contextual research, and policy development are areas that require enormous development to match the needs of the African continent.