In December 2019, the new coronavirus outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was classified as a major global health threat.¹ The novel coronavirus causes a severe acute respiratory syndrome that typically manifests with acute respiratory symptoms such as cough and dyspnoea, joint aches, fatigue, myalgia, and flu-like symptoms. Asymptomatic cases have also been documented.^2,3 Because of various waves experienced, coronavirus disease 2019 (COVID-19) cases reported globally have breached over 600 million cases with approximately 6.5 million fatalities. Various studies have indicated that pre-existing comorbidities and older age were associated with deleterious effect in COVID-19 patients.^2,4 It has been shown that in some patients, COVID-19 infection aggravated co-existing disorders through the host immune response and frequently revealed underlying diseases with rapid progression.³

The effects of comorbidities on a variety of diseases have been extensively studied globally.^4,5 People with underlying health difficulties have severe, life-threatening sickness and significant mortality, according to a systematic review and meta-analysis on the frequency of comorbidities in the Middle East Respiratory Syndrome coronavirus (MERS-CoV).⁶

Non-communicable diseases (NCDs) such as hypertension, type 2 diabetes, obesity and being overweight, are prevalent and contribute to the burden of disease in South Africa.⁷ Chronic comorbid conditions are typically difficult to control for many reasons, including an unorganised healthcare system, disruptions in the supply of medications and a lack of health professional skills and ability.⁸ Therefore, prevention and control of comorbidities are crucial to avert the risk of severe COVID-19 illness and death.⁷

Most hospitalised COVID-19 infected patients required respiratory care because of pneumonia. Those with comorbidities developed severe form of COVID-19 disease that necessitated high or intensive care unit (ICU) admission.

The primary cause of COVID-19 admissions at Pietersburg hospital was pneumonia with many having concomitant conditions. The goal of the study was to investigate factors that predicted the outcome of patients with COVID-19 infection and any associated negative consequences at Pietersburg Hospital.

During the period of the study, a total of 463 patients with confirmed COVID-19 infection were admitted at Pietersburg hospital. Nineteen patients were excluded for not meeting the inclusion criteria. The study sample comprised 225 (50.7%) female and 219 (49.3%) male participants, with a median age of 57 (13–96) years (Figure 1).

Most hospitalised patients were aged between 50 years and 64 years (34.0%). The hospitalised adolescent patients were not severely affected. The adolescent group falling within the age category of 12–17 years only contributed 1.1% of the disease versus 67.6% of the adult (18–64 years) and 31.3% of the elderly groups (65 years and above) (Figure 2).

Of the 444 patients, 311 (70%) had comorbidities, namely, hypertension (n = 208 [51%]), diabetes (n = 152 [38%]), human immunodeficiency virus (HIV) (n = 54 [24%]), chronic renal failure (n = 32 [8.5%]), cardiac disease (n = 27 [7%]), asthma (n = 20 [5%]), chronic obstructive pulmonary disease (COPD) (n = 14 [3.8%]), malignancy (n = 12 [3%]) and active tuberculosis (TB) (n = 5 [1.5%]) (Table 1).

A total of 159 patients (36%) hospitalised with COVID-19 died (82 male [51.6%] and 77 female [48.4%] patients) (p = 0.48) (78 elderly patients [49.1%] and 81 adults [50.9%]). No death occurred in the adolescent group (Table 2). A total of 392 patients with COVID-19 were admitted to the general ward and 52 persons required admission to an advanced level of care (i.e. high care and ICU, respectively). The majority of patients who were hospitalised and admitted to the general ward, required supplemental oxygenation (84.2%). However, only 31 (7%) patients required mechanical ventilation in the ICU. Given the high number of patients who were admitted (N = 444), more than 31 patients surely needed escalation to ICU (Table 3). However, on a multivariable analysis, ICU admission was an independent risk factor for mortality (Table 4). The ICU admission did not improve the odds of patient survival.

In terms of comorbidities present, only hypertension and diabetes (p = 0.0240 and 0.0081, respectively) were significantly related to death on univariate analysis (Table 2). On multivariable analysis, however, hypertension and diabetes were no longer significant (Table 4). Communicable diseases, such as active tuberculosis (TB) and HIV, with only five and 54 cases reported, respectively, had no significant impact on survival (p = 0.291 and p = 0.201). Regarding respiratory illnesses, COPD and asthma collectively, fared better as they had more survival than deaths (Table 2). Smoking, as a risk factor, did not seem to contribute much negatively to the adverse outcome as expected, probably because of lesser individuals self-reporting to be current or previous smokers.

Using the logistic regression model, the two predictor variables, age and ICU admission were significantly associated with the odds of non-survival. Older age was a significant risk factor for COVID-19-related death. The odds of dying increased by 1.044-fold for every additional year of age (odds ratio [OR]: 1.044; 95% CI: 1.029–1.062). Being admitted to the ICU was an independent predictor of mortality, which increased the odds of non-survival three-fold (OR: 3.325, 95% CI: 2.099–4.989). The average length of hospitalisation to reach an endpoint of non-survival was 4 days (Figure 3 and Table 4).

Comorbidities predispose patients with COVID-19 infection to worse clinical outcomes.^1,7,9,10 Naturally, not every pre-existing comorbidity has the same dangers. For instance, in this global outbreak, the three most significant pre-existing conditions, namely hypertension, cardiovascular disease and diabetes were primarily linked to illness severity and unfavourable outcomes.⁴ However, in our study, hypertension and diabetes were not independent predictors of the adverse outcome, only age and ICU admission were. This differed with a trend observed in studies from China and the United States (US).^9,11 The missing data might have had an impact on multivariable analysis. Tuberculosis and HIV seemingly had no negative impact on the outcome, despite available data that showed their prevalence.^10,12,13 The plausible explanation could be because of under-investigation of these conditions during the pandemic because of the lockdown restrictions and staff shortage in health facilities. This created a barrier for healthcare access and led to reduction in HIV and TB testing.¹⁴

In certain studies, being ≥ 60 years of age was associated with an increased risk of disease severity.^1,15,16 Furthermore, we demonstrated increased risk of death for each additional year of age (OR: 1.044; 95% CI: 1.029–1.062). The OR below one was considered a protective factor. The majority of patients treated throughout the study period were adults (between 50 years and 64 years old) and elders (65 years and above) with coexisting disorders, increasing their risk of developing severe disease. In South Africa, the second wave of COVID-19 saw increased hospitalisation of patients between 40 years and 64 years and above 65 years.¹⁰ The study underscored the importance of capacitating the healthcare service in order to protect the most vulnerable groups of society such as the elderly population. Vaccination against COVID-19 infection in older people offers a more significant protection. It had been shown to reduce hospitalisation and mortality.¹⁷

In our study, 49 patients (11%) required ICU admission, with 31 (7%) requiring mechanical ventilation. As compared to the data emanating from the US, one study reported that 809 (14.2%) patients received ICU care, with 695 (12.2%) of them receiving mechanical ventilation.⁹ The disparity in terms of available access to advanced care cannot be ignored. Our study was carried out in a setting with limited resources as compared to the US study. In the African COVID-19 Critical Care Outcomes study (ACCCOS), a combined 3752 (55.3%) out of 6779 patients from 64 centres in 10 countries were admitted to ICU. The 30-day in-hospital mortality was 48.2%.¹⁶

Our in-hospital mortality was 36%. This was associated with a shorter length of hospitalisation, with an average of 4 days. This could be because of severe disease on admission, late patient presentation or delay in receiving urgent medical care as a result of an overwhelmed healthcare facility. In comparison, a regional hospital in Mthatha, Eastern Cape province, which also serves a similar mainly rural population as Pietersburg Hospital, had 46% mortality rate, way above the provincial rate (27.5%) and national rate (18.3%).¹⁸ In this study, a high volume of patients coupled with a lack of resources and late presentation contributed largely to the high in-hospital mortality.¹⁸ In a large, geographically inclusive retrospective study performed in the US, the in-hospital mortality rate was 10.6% in March 2020 with an increased trend towards 19.7% in April 2020, declining to 9.3% in November 2020. This improvement was largely because of better understanding of the disease, improved clinical care and ventilation strategies.¹⁹ South Africa experienced more in-patient mortality during the second wave. This was driven largely by the new Beta variant that peaked in January 2021, coupled with increased admissions of older patients and increased healthcare facility load.¹⁰ The Limpopo province was also hard-hit, with 90% deaths reported during the second wave. The case fatality rate was 27.5%.²⁰

There was no significant association between non-survival and communicable diseases such as active TB and HIV, respiratory illnesses such as asthma and chronic obstructive pulmonary disease. This correlates with the findings by ACCCOS multicentre cohort study with the exception that in their case, HIV was associated with increased mortality in adults admitted with COVID-19.¹⁶ In our case, fewer patients reported having HIV or active TB. This could be attributed to the under-investigation of patients who were admitted. A larger, countrywide research is suggested on survivors of COVID-19 infection to further understand the long-term impact of the pandemic.

Obesity has been strongly associated with COVID-19 mortality in the literature.⁵ Even though it was associated with comorbidities including hypertension, diabetes, and cardiovascular illnesses, this was frequently linked to reduced lung capacity exacerbated by viral and secondary pneumonia.⁵ In our investigation, obesity was determined based on the clinician’s subjective assessment as the standard method of calculating body mass index (BMI) was not objectively used. This might have been because the COVID-19 infection was so severe that the majority of patients became oxygen dependent, making it challenging to measure objectively. Another explanation could be that even individuals with mild COVID-19 disease were not properly identified because calculating BMI is not a typical practice in our setting. Therefore, in our study, the effect of obesity was not statistically significant and we acknowledge the limitation that obesity was not objectively measured, hence the result should be taken with caution.

According to the study, the risk factors that were independently associated with in-hospital mortality were older age and ICU admission. Comorbidities did not contribute significantly to the outcome in this study, as reported elsewhere.^9,11