Re: chronic Q-fever-related complications and mortality: data from a nationwide cohort

Abstract

We read with interest the article by van Roeden et al. about the chronic Q fever mortality rate in The Netherlands. We were surprised to observe that the mortality rate reported from The Netherlands was 3.3 times higher than that observed from the French National Reference Center for Q fever [1,2]. In our experience, among the 678 patients with persistent cardiovascular focalized infection diagnosed between 1991 and 2016, 55 died (55/678, 8%): 43 with endocarditis (43/533, 8%) and 16 with a vascular infection (16/145, 11%); among these four had both Coxiella burnetii endocarditis and vascular persistent infection (4/ 49, 8.1%) [2]. The mortality rate was 1.8 (95%CI 1.4e2 .3) per 100 person-years and the 5-year survival for cardiovascular persistent C. burnetii infection was 73%.(see Table 1) In The Netherlands after the 2009e2011 epidemics, of the 439 patients diagnosed with chronic Q fever 118 died (27%), and of these 54 (35%) had a vascular infection, 27 (32%) had endocarditis, and 20 (47%) had both C. burnetii endocarditis and vascular infection. The 5-year survival for proven and probable chronic Q fever was 64% [1]. Persistent C. burnetii cardiovascular infection is a deadly disease if left untreated, but is ultimately curable, so how can the high mortality rate in The Netherlands be explained?

‘Chronic Q fever-related complications and mortality: data from a nationwide cohort’ – Author’s reply

“…In conclusion, chronic Q fever is a potential lethal disease. We agree with and underline the importance of the suggestion that optimization of diagnosis, treatment and follow-up must lead to improvement of the prognosis of chronic Q fever patients, as suggested by Melenotte et al [1].…”

“…Another issue pointed out by the authors is that a proportion of patients did not receive antibiotic therapy [1]. Indeed, 33% (n ¼ 144) of all patients did not receive antibiotic treatment.…”

“…To the Editor, Melenotte et al point out that in patients with possible chronic Q fever, a PET-CT scan was not routinely performed and that an infectious focus had not been ruled out in all patients [1,2]. Diagnostic work-up in patients with possible chronic Q fever was not standardized: a PET-CT scan was performed in 52% (n ¼ 60) and echocardiography in 72% (n ¼ 83) of patients.…”

The prognostic value of serological titres for clinical outcomes during treatment and follow-up of patients with chronic Q fever

“…Also, the study from Million et al suffers from potential survival bias, because it was performed in a tertiary referral centre. Patients that died early in the course of the disease would not have been referred [17,18].…”