Table 2

Logistic regression models for risk of complaints within 2 years, and Predicted Risk Of New Event (PRONE) scoring system, derived from the ORs in model 2

Model 1
OR (95% CI)
Model 2
OR (95% CI)
Model 3
OR (95% CI)
PRONE score
Complaint number
 1 (ref)1.001.001.000
 21.29 (1.11 to 1.49)1.35 (1.20 to 1.51)1.82 (1.66 to 2.00)1
 31.85 (1.56 to 2.20)1.91 (1.65 to 2.22)2.76 (2.43 to 3.14)2
 42.48 (2.01 to 3.07)2.64 (2.18 to 3.20)3.98 (3.35 to 4.72)4
 53.29 (2.51 to 4.31)3.41 (2.67 to 4.35)5.36 (4.27 to 6.73)5
 64.35 (3.11 to 6.10)4.30 (3.15 to 5.87)6.88 (5.11 to 9.25)5
 74.76 (3.08 to 7.34)5.01 (3.35 to 7.49)8.51 (5.85 to 12.4)6
 84.44 (2.78 to 7.08)4.79 (3.08 to 7.43)7.98 (5.23 to 12.2)6
 96.51 (3.38 to 12.53)6.73 (3.68 to 12.3)11.1 (6.19 to 19.8)7
 10+18.89 (9.76 to 36.56)18.3 (10.2 to 32.8)33.8 (19.1 to 59.7)11
Doctor's specialty
 Anaesthesia (ref)1.001.000
 Radiology1.00 (0.47 to 2.12)1.06 (0.51 to 2.22)0
 Other specialties0.97 (0.63 to 1.49)1.12 (0.76 to 1.64)0
 Internal medicine1.40 (1.04 to 1.88)1.50 (1.12 to 1.99)1
 Ophthalmology1.36 (0.94 to 1.96)1.58 (1.12 to 2.23)2
 General practice1.61 (1.23 to 2.10)1.75 (1.35 to 2.26)2
 Psychiatry1.94 (1.44 to 2.62)2.00 (1.49 to 2.68)3
 Orthopaedic surgery2.02 (1.49 to 2.74)2.26 (1.68 to 3.03)3
 Other surgery2.11 (1.56 to 2.86)2.30 (1.72 to 3.09)3
 General surgery2.11 (1.51 to 2.95)2.46 (1.79 to 3.38)3
 Obstetrics and gynaecology2.36 (1.73 to 3.23)2.51 (1.85 to 3.39)3
 Dermatology2.73 (1.89 to 3.96)3.15 (2.16 to 4.59)4
 Plastic surgery3.98 (2.84 to 5.57)4.44 (3.21 to 6.13)6
Time since previous complaint
 1–2 years (ref)1.001.000
 6 months to 1 year1.23 (1.04 to 1.47)1.20 (1.02 to 1.43)1
 Less than 6 months1.68 (1.44 to 1.95)1.77 (1.53 to 2.04)2
Doctor's sex
 Female (ref)1.001.000
 Male1.45 (1.27 to 1.66)1.51 (1.33 to 1.71)2
Doctor's age
 22–34 years (ref)1.00
 35–65 years1.41 (1.10 to 1.82)
Location of practice
 Urban (ref)1.00
 Rural1.12 (1.01 to 1.24)
Complaint issue
 Other issue (ref.)1.00
 Clinical care1.02 (0.9 to 1.16)
C-statistic (adjusted for optimism)0.690.700.66