Table 1

Case-crossover analysis comparing the incidence of invasive procedures (IPs) in the 3-month case period and the preceding 12-month control period for 14 731 patients admitted with IE

Invasive procedures (ISPs)Case period (3 m)Control period (12 m)Unadjusted step model†Adjusted step model‡Adjusted hinge model§
Total proc*Proc/m*Total proc*Proc/m*OR95% CIOR95% CIP valueOR95% CIP value
Cardiac procedures
Coronary angiography36612299182.61.481.31 to 1.671.050.88 to 1.250.7761.040.97 to 1.120.403
Coronary artery bypass graft (CABG)12412141.80 to 8.912.990.75 to 11.960.2531.620.96 to 2.730.132
Percutaneous coronary procedures and stent implantation5418978.12.251.61 to 3.151.590.94 to 2.680.2111.281.03 to 1.580.066
Implantation of cardiac pacemakers/defibrillators463154.3672562.812.50 to 3.171.541.27 to 1.85<0.0011.291.19 to 1.39<0.001
Percutaneous valve procedures93292.41.250.59 to 2.662.570.78 to 8.450.2781.610.99 to 2.600.115
Dental procedures
Extractions or surgical removal of teeth5418816.82.681.90 to 3.782.141.22 to 3.760.0471.271.02 to 1.590.082
Other oral surgical procedures134.3252.12.101.07 to 4.121.590.56 to 4.530.5901.140.75 to 1.750.687
Scaling and gingival procedures10.310.140.25 to 63.922.990.02 to 363.520.7530.550.08 to 4.040.611
ENT procedures
Tonsillectomy and adenoidectomy20.760.51.330.27 to 6.610.280.03 to 2.390.4720.580.21 to 1.560.376
Nasal packing/nasal intubation237.7594.91.600.97 to 2.640.710.35 to 1.440.5720.990.73 to 1.330.925
GI procedures
Upper GI endoscopic procedures (gastric, duodenum, jejunum, ileum)627209101484.52.592.34 to 2.871.581.34 to 1.85<0.0011.301.22 to 1.39<0.001
Lower GI endoscopic procedures (including sigmoid and rectum)33311165654.72.071.81 to 2.371.661.35 to 2.04<0.0011.231.13 to 1.34<0.001
Colonic surgery (including appendicectomy)289.3594.91.91.21 to 2.981.480.74 to 2.950.4671.010.76 to 1.350.911
Endoscopic retrograde cholangio-pancreatic procedures258.3574.81.811.12 to 2.940.940.46 to 1.890.8530.780.57 to 1.060.198
GU procedures
Cystoscopy procedures15551.750141.81.261.05 to 1.530.920.70 to 1.200.7750.940.83 to 1.050.391
Endoscopic prostate procedures3812.710891.410.97 to 2.050.550.33 to 0.920.0840.720.57 to 0.910.019
Haematology procedures
Blood transfusion/red cell/plasma exchange29598.3660552.842.35 to 3.431.331.01 to 1.760.1291.21.07 to 1.350.012
Bone marrow puncture9933144122.962.27 to 3.871.761.16 to 2.690.0391.281.08 to 1.520.018
Obstetric and gynaecological procedures
Abortion/dilatation and curettage41.3110.91.460.46 to 4.631.690.29 to 9.720.7542.070.99 to 4.330.120
Vaginal delivery72.3292.40.970.42 to 2.200.960.31 to 2.980.8981.340.83 to 2.150.380
Caesarean delivery20.7100.80.80.18 to 3.650.710.10 to 5.240.8051.280.56 to 2.940.639
Respiratory procedures
Bronchoscopic procedures51177262.882.00 to 4.131.871.04 to 3.340.1181.331.06 to 1.680.049
Skin procedures
Skin and wound management procedures10735.729524.61.461.17 to 1.830.920.67 to 1.270.7650.960.84 to 1.100.600
  • P values in red=significant positive association between the ISP and subsequent IE after Benjamini-Hochberg correction. P values in purple=significant negative association between ISP and subsequent IE after Benjamini-Hochberg correction.

  • *A maximum of one procedure of each type per patient was counted each month.

  • †Period-adjusted OR of ISPs in case period (3 months prior to IE admission) compared with the 12 month control period (15 to 4 months prior to IE admission) calculated using a mixed-effects logistic regression model with the patient as the random effect.

  • ‡OR of ISPs in case period (3 months prior to IE admission) compared with control period (15 to 4 months prior to IE admission) calculated using a mixed-effects logistic regression model adjusted for the month (1–15) and date of IE admission (with the patient as the random effect).

  • §OR of ISPs for each month increase in the case period (3 to 1 months prior to IE admission) compared with control period (15 to 4 months prior to IE admission) calculated using a mixed-effects logistic regression model adjusted for month and date of IE admission (with patient as the random effect).

  • IE, infective endocarditis; ISPs, invasive procedures; m, month; proc, procedures.