Volume 18, Number 4—April 2012
Identification of Risk Factors for Chronic Q Fever, the Netherlands
|Risk factor*†||All chronic Q fever
||Proven and probable chronic Q fever
||Proven chronic Q fever
|OR (95% CI)||p value||OR (95% CI)||p value||OR (95% CI)||p value|
|Valvular surgery†‡||31.5 (3.99–249)||0.001||47.7 (5.87–387)||0.000||43.6 (4.70–405)||0.001|
|Vascular prosthesis‡§||10.4 (2.17–50.0)||0.003||14.9 (2.96–75.2)||0.001||26.8 (4.88–147)||0.000|
|Aneurysm§¶||8.65 (1.74–42.9)||0.008||13.5 (2.60–70.4)||0.002||25.9 (4.55–147)||0.000|
|Renal insufficiency¶#||–||–||9.08 (1.44–57.2)||0.019||16.0 (2.06–123)||0.008|
|Nonhematologic malignancy||3.90 (1.33–11.5)||0.013||–||–||–||–|
|Age, continuous||1.03 (1.01–1.06)#||0.005||1.06 (1.03–1.09)#||0.000||1.06 (1.02–1.11)#||0.005|
*OR, odds ratio.
†Possible risk factors entered in all analyses: age, vascular prosthesis, aortic aneurysm, other vascular surgeries, peripheral arterial disease, cerebrovascular disease, valvular surgery, valvular disease (nonsurgical), ischemic cardiac disease, other cardiac history, hypertension, dyslipidemia, diabetes, nonhematologic malignancy, renal insufficiency. Immune disorder was also entered in the analyses of proven and probable chronic Q fever and of proven chronic Q fever. Pacemaker was also entered in the analysis of proven chronic Q fever.
‡Valvular surgeries in the proven group are subdivided into biological valve (n = 6), prosthetic valve (n = 3), and valve repair (n = 1) all located in the aortic valve (n = 10). Within the controls there were no patients with history of valvular surgery.
§Locations of vascular prostheses in proven group were infrarenal and iliac (n = 6), infrarenal (n = 4), thoracic (n = 2), and unknown (n = 2). Types of vascular prosthesis were Y-prosthesis (n = 7), endovascular aneurysm repair (n = 2), stent graft (n = 2), Bentall (n = 1), and unknown (n = 2). For the 2 control patients, specifications of the prostheses were unknown.
¶Locations of aneurysms in proven group were infrarenal (n = 6), infrarenal and iliac (n = 2), and suprarenal, infrarenal, and iliac (n = 1). Within the control group, aneurysms were infrarenal and iliac (n = 2).
#Observed stages of chronic kidney disease according to the Kidney Disease Outcome Quality Initiative guidelines (28) in the proven group were stage 3 (n = 6), stage 4 (n = 2), and stage 5 (n = 1) and in the controls solely stage 3 (n = 2).
#OR per year of increasing age.