Background: Middle East respiratory syndrome (MERS) is a severe respiratory illness that was first identified in 2012, following the outbreaks in the Kingdom of Saudi Arabia (KSA). The main aim of this study was to determine the prognosis of MERS patients with comorbidities, through the measurement of the fatality rate. Methods: This is a retrospective cohort study that included patients diagnosed with MERS, from 2012 to 2019, within the KSA. The fatality rate was measured for cases with and without comorbidities, based on various classifications of chronic disease. Results: Of the patients diagnosed with MERS and comorbidities, 327 (45%) patients were deceased, whereas only 49 (21%) of the MERS cases without comorbidities died. Based on the fatality rates, MERS cases with endocrine diseases, renal diseases, other comorbidities (including septic shock and obesity), and cardiovascular diseases were the most vulnerable, with fatality rates of 49% (247), 48% (41), 47% (77), and 41% (558), respectively. Conclusion: This study suggests that the prognosis for MERS cases with comorbidities is poorer than for cases without comorbidities. Male gender and older age were associated with increased cases of fatality rate.

Keywords: MERS, comorbidities, fatality rate, public health