The impact on primary care of a large waterborne campylobacter outbreak in Norway: a controlled observational study

Figures & data

Table 1. Summarized characteristics for all contacts with daytime general practice and out-of-hours service in the outbreak period and the control period.

	All	Outbreak	Control
	N = 8326	n = 4798 (58%)	n = 3528 (42%)	OR [95% CI]^a	Chi Square^b
Sex
Female	4698	2667 (56%)	2031 (58%)	0.92 [0.84–1.01]
Male	3628	2131 (44%)	1497 (42%)	1.08 [0.99–1.18]	0.071
Age range (yrs.)^c
0–4	679	452 (9%)	227 (6%)	1.51 [1.28–1.78]
5–14	656	380 (8%)	276 (8%)	1.01 [0.86–1.19]
15–24	982	542 (11%)	440 (13%)	0.89 [0.78–1.02]
25–34	1039	617 (13%)	422 (12%)	1.09 [0.95–1.24]
35–44	1046	622(13%)	424 (12%)	1.09 [0.96–1.24]
45–54	1277	748 (16%)	529 (15%)	1.05 [0.93–1.18]
55–64	886	461 (10%)	425 (12%)	0.78 [0.67–0.89]
65–74	923	526 (11%)	397 (11%)	0.97 [0.85–1.11]
75–84	590	323 (7%)	267 (8%)	0.88 [0.75–1.04]
≥ 85	248	127 (3%)	121 (3%)	0.77 [0.59–0.99]	< 0.000
Contact reasons
Gastroenteritis	1316	1288 (27%)	28 (1%)	45.87 [31.46–69.47]
Outbreak concern	141	141 (3%)	NA^d	NA
Other	6869	3369 (70%)	3500 (99%)	0.02 [0.01–0.03]	< 0.000
Contact types
Consultation	5393	2830 (59%)	2563 (73%)	0.54 [0.49–0.60]
Telephone advice	1486	1197 (25%)	289 (8%)	3.73 [3.24–4.28]
Other^e	1338	717 (15%)	621 (18%)	0.82 [0.73–0.93]
Doctor’s visit	77	37 (1%)	40 (1%)	0.68 [0.43–1.09]
Ambulance^f	32	17 (0%)	15 (0%)	0.83 [0.39–1.79]	< 0.000

^aOutbreak as exposure.

^bChi square p-value per group (sex, age, contact reason and contact type).

^cMaximum age 99 yrs. First group spans 5 yrs.

^dNot applicable.

^eBilling, opening hours, prescription renewal, etc.

^fAssessment or physician advice to ambulance regarding a patient.

Table 2. Summarized characteristics of contacts with daytime general practice and out-of-hours service during the outbreak and control period.

	Daytime general practice				Out-of-hours service
	Outbreak	Control		Chi square^b	Outbreak	Control		Chi square
	n = 2957	n = 2802	OR [95% CI]^a	p-value	n = 1841	n = 726	OR [95% CI]	p-value
Sex
Female	1684 (57%)	1631 (58%)	0.95 [0.85–1.06]		983 (53%)	400 (55%)	2.99 [6.61–3.41]
Male	1273 (43%)	1171 (42%)	1.05 [0.95–1.17]	.334	858 (47%)	326 (45%)	3.10 [2.69–3.58]	.436
Age range (yrs.)^c
0–4	129 (4%)	112 (4%)	1.10 [0.84–1.43]		323 (18%)	115 (16%)	2.86 [2.29–3.60]
5–14	150 (5%)	190 (7%)	0.73 [0.58–0.92]		230 (13%)	86 (12%)	2.66 [2.06–3.47]
15–24	341 (12%)	347 (12%)	0.92 [0.78–1.08]		201 (11%)	93 (13%)	2.12 [1.64–2.76]
25–34	378 (13%)	337 (12%)	1.07 [0.91–1.26]		239 (13%)	85 (12%)	2.81 [2.17–3.66]
35–44	397 (13%)	362 (13%)	1.05 [0.89–1.22]		225 (12%)	62 (9%)	3.64 [2.72–4.93]
45–54	500 (17%)	444 (16%)	1.08 [0.94–1.25]		248 (14%)	85 (12%)	2.93 [2.26–3.81]
55–64	322 (11%)	351 (13%)	0.85 [0.72–1.00]		139 (8%)	74 (10%)	1.82 [1.35–2.46]
65–74	410 (14%)	348 (12%)	1.14 [0.97–1.33]		116 (6%)	49 (7%)	2.29 [1.62–3.29]
75–84	236 (8%)	224 (8%)	0.99 [0.82–1.21]		87 (5%)	43 (6%)	1.94 [1.33–2.88]
≥ 85	94 (3%)	87 (3%)	1.02 [0.75–1.39]	.067	33 (2%)	34 (5%)	0.92 [0.55–1.53]	<.000
Contact reasons
Gastroenteritis	301 (10%)	18 (1%)	17.53 [10.86–30.06]		987 (53%)	10 (1%)	139.88 [75.43–293.22]
Outbreak concern	12 (0%)	NA^d	NA		129 (7%)	NA	NA
Other	2 644(90%)	2 784 (99%)	0.55 [0.32–0.88]	<.000	725 (40%)	716 (99%)	0.94 [0.84–1.07]	<.000
Contact types
Consultation	2 228 (75%)	2 253 (80%)	0.74 [0.66–0.85]		602 (33%)	310 (43%)	2.05 [1.76–2.39]
Telephone advice	87 (3%)	21 (1%)	4.01 [2.45–6.83]		1 110 (60%)	268 (37%)	5.68 [4.89–6.60]
Other^e	635 (22%)	518 (19%)	1.21 [1.06–1.38]		82 (5%)	103 (14%)	0.75 [0.55–1.01]
Doctor’s visit	7 (0%)	10 (0%)	0.66 [0.21–1.93]		30 (2%)	30 (4%)	0.95 [0.56–1.63]
Ambulance^f	0 (0%)	0 (0%)	NA	<.000	17 (1%)	15 (2%)	1.07 [0.50–2.31]	<.000

^aOutbreak as exposure.

^bChi square per group (sex, age, contact reason and contact type).

^cMaximum age 99 yrs. First group spans 5 yrs.

^dNot applicable.

^eBilling, opening hours, prescription renewal, etc.

^fAssessment or physician advice to ambulance regarding a patient.

Figure 1. Combined number of gastroenteritis and gastroenteritis concern contacts (grey) shown together with number of all contacts (black), during the outbreak for general practice and out-of-hours service.

Figure 2. Gastroenteritis cases during the outbreak period, shown by contact date with OOH service or daytime general practice.

Figure 3. Incoming calls on Thursday June 6, when the outbreak became publicly known, compared to Thursday May 16 (control period) at the out-of-hours service in Askøy municipality. Group width is fifteen minutes.