General Practitioner Attendance in Proximity to HPV Vaccination: A Nationwide, Register-Based, Matched Case–Control Study

Figures & data

Table 1 Characteristics of Matching Variables and Covariates for Cases and Controls

Characteristics	Cases (N = 1458)	Controls (N = 7212)
Matching variables
Age at vaccination, years, n (%)
12–15	973 (66.7)	4852 (67.3)
16–20	112 (7.7)	550 (7.6)
21–25	233 (16.0)	1149 (15.9)
26+	140 (9.6)	661 (9.2)
Region, n (%)
North Jutland	179 (12.3)	887 (12.3)
Central Jutland	269 (18.4)	1337 (18.5)
South Denmark	292 (20.0)	1443 (20.0)
Capital	412 (28.3)	2047 (28.4)
Zealand	306 (21.0)	1498 (20.8)
Year of vaccination, n (%)
2008	222 (15.2)	1107 (15.3)
2009	275 (18.9)	1370 (19.0)
2010	144 (9.9)	709 (9.8)
2011	140 (9.6)	696 (9.7)
2012	353 (24.2)	1757 (24.4)
2013	226 (15.5)	1112 (15.4)
2014	70 (4.8)	326 (4.5)
2015	28 (1.9)	135 (1.9)
No. of vaccine doses, n (%)
1	105 (7.2)	506 (7.0)
2	233 (16.0)	1136 (15.8)
3+	1120 (76.8)	5570 (77.2)
Covariates
Psychiatric condition, n (%)
Yes	168 (11.5)	503 (7.0)
No	1290 (88.5)	6709 (93.0)
Chronic somatic condition, n (%)
Yes	130 (8.9)	401 (5.6)
No	1328 (91.1)	6811 (94.4)
Asthmatic condition, n (%)
Yes	235 (16.1)	811 (11.3)
No	1223 (83.9)	6401 (88.7)
Maternal covariates
Age at vaccination, years, n (%)
<41	430 (29.5)	2152 (29.8)
42–45	371 (25.4)	1822 (25.3)
46–50	360 (24.7)	1627 (22.6)
51+	297 (20.4)	1544 (21.4)
Missing	–	67 (0.9)
Educational level, n (%)
Primary school	290 (19.9)	1365 (18.9)
Upper secondary/vocational training	679 (46.6)	3032 (42.0)
Short cycle higher education	75 (5.1)	379 (5.3)
Bachelor/vocational bachelor	321 (22.0)	1691 (23.5)
Master/PhD program	61 (4.2)	463 (6.4)
Missing	32 (2.2)	282 (3.9)
Employment status, n (%)
Employed, lowest income	454 (31.1)	2081 (28.8)
Employed, middle income	242 (16.6)	1169 (16.2)
Employed, highest income	234 (16.1)	1489 (20.7)
Self-employed	54 (3.7)	293 (4.1)
Outside workforce/Student	204 (14.0)	898 (12.4)
Retirement/pension	129 (8.9)	459 (6.4)
Employed, unspecified	123 (8.4)	659 (9.1)
Missing	18 (1.2)	164 (2.3)

Figure 1 Mean yearly GP contacts and the ratio of the adjusted IRR from prior to vaccination compared to after vaccination between cases and matched controls (entire study population). Cases: 1,458; Controls: 7,212. ** Date of vaccination included.

Table 2 Mean Yearly GP Contacts, the Incidence Rate Ratios (IRR) of Mean Yearly GP Contacts, and the Ratio of the Adjusted IRR from Prior to Vaccination Compared to After Vaccination Between Cases and Matched Controls^a

	Mean Yearly GP Contacts		IRR (Crude)	IRR (Adjusted)^b	Ratio of IRR (R-IRR)
All	Cases	Controls
Prior to vaccination	4.67	3.40	1.37 [1.32; 1.43]	1.33 [1.28; 1.38]	1.40 [1.36; 1.44]
After vaccination	9.13	4.77	1.91 [1.84; 2.00]	1.86 [1.79; 1.93]
Vaccinated in 2008–2009
Prior to vaccination	3.79	2.79	1.36 [1.27; 1.45]	1.37 [1.28; 1.46]	1.35 [1.29; 1.42]
After vaccination	8.66	4.72	1.84 [1.72; 1.95]	1.86 [1.74; 1.98]
Vaccinated in 2010–2012
Prior to vaccination	4.92	3.71	1.33 [1.25; 1.41]	1.29 [1.22; 1.36]	1.38 [1.33; 1.44]
After vaccination	8.88	4.85	1.83 [1.72; 1.95]	1.78 [1.69; 1.89]
Vaccinated in 2013–2015
Prior to vaccination	5.88	3.77	1.56 [1.41; 1.72]	1.45 [1.33; 1.58]	1.56 [1.47; 1.67]
After vaccination	10.48	4.31	2.43 [2.19; 2.70]	2.27 [2.07; 2.48]
Under 15 years
Prior to vaccination	3.45	2.52	1.37 [1.31; 1.43]	1.41 [1.34; 1.48]	1.44 [1.39; 1.49]
After vaccination	7.53	3.84	1.96 [1.87; 2.05]	2.03 [1.93; 2.13]
Above 15 years
Prior to vaccination	8.91	6.06	1.47 [1.38; 1.56]	1.32 [1.25; 1.40]	1.32 [1.27; 1.38]
After vaccination	14.52	7.50	1.94 [1.82; 2.06]	1.74 [1.65; 1.85]

Notes: ^aControls are matched on age at first vaccine registration, time of first vaccine registration (±2 months), region of residence and number of doses received. ^bAdjusted for prior chronic somatic condition, prior asthmatic condition, prior psychiatric condition, maternal age at vaccination, maternal educational level and maternal employment status.

Figure 2 Mean yearly GP contacts and the ratio of the adjusted IRR from prior to vaccination compared to after vaccination between cases and matched controls. (A) 2008–2009. Cases: 497; Controls: 2,477. (B) 2010–2012. Cases: 637; Controls: 3,162. (C) 2013–2015. Cases: 324; Controls: 1,573. **Date of vaccination included.

Figure 3 Mean yearly GP contacts and the ratio of the adjusted IRR from prior to vaccination compared to after vaccination between cases and matched controls. (A) Under 15 years. Cases: 973; Controls: 4,852. (B) Above 15 years. Cases: 485; Controls: 2,360. **Date of vaccination included.

Figure 4 Mean monthly GP contacts 12 months prior to and 12 months following vaccination divided into three months intervals (entire study population). Cases: 1,458; Controls: 7,212. **Date of vaccination included.