A Comparative Study of Clinical Presentation and Risk Factors for Adverse Outcome in Patients Hospitalised with Acute Respiratory Disease Due to MERS Coronavirus or Other Causes

Abstract

Middle East Respiratory syndrome (MERS) first emerged in Saudi Arabia in 2012 and remains a global health concern. The objective of this study was to compare the clinical features and risk factors for adverse outcome in patients with RT-PCR confirmed MERS and in those with acute respiratory disease who were MERS-CoV negative, presenting to the King Fahad Medical City (KFMC) in Riyadh between October 2012 and May 2014. The demographics, clinical and laboratory characteristics and clinical outcomes of patients with RT-PCR confirmed MERS-CoV infection was compared with those testing negative MERS-CoV PCR. Health care workers (HCW) with MERS were compared with MERS patients who were not health care workers. One hundred and fifty nine patients were eligible for inclusion. Forty eight tested positive for MERS CoV, 44 (92%) being hospital acquired infections and 23 were HCW. There were 111 MERS-CoV negative patients with acute respiratory illnesses included in this study as "negative controls". Patient with confirmed MERS-CoV infection were not clinically distinguishable from those with negative MERS-CoV RT-PCR results although diarrhoea was commoner in MERS patients. A high level of suspicion in initiating laboratory tests for MERS-CoV is therefore indicated. Variables associated with adverse outcome were older age and diabetes as a co-morbid illness. Interestingly, co-morbid illnesses other than diabetes were not significantly associated with poor outcome. Health care workers with MERS had a markedly better clinical outcome compared to non HCW MERS patients.

Fig 1. Time from hospital admission to death.

A: Comparing patients with MERS-CoV infection (red line) and those negative for MERS-CoV (black line) (p = 0.01). B: Comparing health care workers with MERS CoV (red dotted line; group1), non-HCW with MERS (red solid line; group 2) and patients without MERS-CoV infection (black solid line; group 3). Log rank test group 1 vs. group 2 p = 0.003; group 2 vs group 3 p = 0.45; group 1 vs group 3 p<0.001.

Fig 2. Time from hospital admission to death stratified by comorbid disease status among MERS positive cases.

Survival analysis was carried out to ascertain impact of co-morbidities on survival in patients with MERS-CoV infection. Black line (group 1): No comorbid disease; Red line (group 2): Diabetes with or without other comorbidities; Green line (group 3): Any other comorbid disease without diabetes. Log rank test: group 1 vs group 2 p = 0.01; Group 1 vs. group 3 p = 0.54; group 2 vs. group 3 p = 0.01.