Peritonsillar Abscess and Antibiotic Prescribing for Respiratory Infection in Primary Care: A Population-Based Cohort Study and Decision-Analytic Model

Article Figures & Data

Table 1

Definition and Data Source for Probabilities

Term	Explanation	Data Source
P(RTI)	Probability of a person consulting with RTI in a 30-day period	From RTI consultation rate per 30 days in CPRD
P(AB\|RTI)	Probability of receiving an AB prescription on the same date as an RTI consultation	From proportion of RTI consultations with AB prescribed, from CPRD
P(PTA)	Probability of PTA, per 30 days	From incidence of PTA in CPRD
P(RTI\|PTA)	Probability of patients with PTA having consulted for an RTI in the 30 days preceding their PTA diagnosis	Proportion of PTA cases with previous RTI consultation, calculated from CPRD
P(PTA\|RTI)	Probability of PTA arising in the 30 days following an RTI consultation
P(PTA\|[AB\|RTI])	Probability of patients with PTA having consulted for an RTI and received AB prescription
P(PTA\|[No AB\|RTI])	Probability of patients with PTA having consulted for an RTI and not received an AB prescription
NNT	The number of additional antibiotic prescriptions required to prevent 1 case of PTA

AB = antibiotic; CPRD = Clinical Practice Research Datalink; NNT = number needed to treat; P = probability; PTA = peritonsillar abscess; RTI = respiratory tract infection.

Table 2

Characteristics of Patients With Peritonsillar Abscess

Characteristic	Total, No. (%)	Male, No. (%)	Female, No. (%)
Total	11,007 (100)	5,817 (53)	5,190 (47)
Age group, y
0-4	72 (1)	42 (1)	30 (1)
5-14	681 (6)	316 (5)	365 (7)
15-24	3,330 (30)	1,737 (30)	1,593 (31)
25-34	2,531 (23)	1,255 (22)	1,276 (25)
35-44	2,415 (22)	1,330 (23)	1,085 (21)
45-54	1,051 (10)	611 (11)	440 (8)
55-64	535 (5)	311 (5)	224 (4)
65-74	278 (3)	153 (3)	125 (2)
75-84	89 (1)	54 (1)	35 (1)
≥85	25 (0)	8 (0)	17 (0)
Period of diagnosis
2002-2006	3,919 (36)	2,042 (35)	1,877 (36)
2007-2011	3,782 (34)	2,039 (35)	1,743 (34)
2012-2017	3,306 (30)	1,736 (30)	1,570 (30)
Comorbidity
Absent	7,864 (71)	4,268 (73)	3,596 (69)
Present	3,143 (29)	1,549 (27)	1,594 (31)
Smoking status
Current smoker	3,758 (34)	2,078 (36)	1,680 (32)
Ex-smoker	1,292 (12)	673 (12)	619 (12)
Non smoker	5,957 (54)	3,066 (53)	2,891 (56)
Season
Winter (Dec-Feb)	2,946 (27)	1,535 (26)	1,411 (27)
Spring (Mar-May)	2,897 (26)	1,530 (26)	1,367 (26)
Summer (June-Aug)	2,624 (24)	1,397 (24)	1,227 (24)
Fall (Sep-Nov)	2,540 (23)	1,355 (23)	1,185 (23)

Table 3

Proportion of Patients With PTA Who Consulted a GP or Were Prescribed Antibiotics Prior to Their First PTA Diagnosis (N = 11,007)

Days Preceding PTA Diagnosis	PTA Patients Consulting For, No. (%)		PTA Patients Prescribed Antibiotic in the Same
Days Preceding PTA Diagnosis	RTI	Any Reason	Period, No. (%)
7	3,406 (30.9)	5,358 (48.7)	2,826 (25.7)
14	3,874 (35.2)	6,215 (56.5)	3,305 (30.0)
30	4,243 (38.5)	6,996 (63.6)	3,782 (34.4)
60	4,556 (41.4)	7,903 (71.8)	4,185 (38.0)

GP = general practitioner; PTA = peritonsillar abscess; RTI = respiratory tract infection.

Table 4

Estimated Number of Antibiotic Prescriptions Required to Prevent 1 Case of PTA by Age Group and Sex

Age Group, y	Antibiotic Prescriptions to Prevent 1 PTA
Age Group, y	Male, No. (95% CI)	Female, No. (95% CI)
0-4	170,895	195,903
	(–3,454,195 to 3,610,347)	(−4,477,555 to 4,509,199)
5-14	25,042 (15,160-63,304)	17,982 (11,927-35,987)
15-24	1,121 (975-1,310)	2,032 (1,770-2,366)
25-34	926 (814-1,063)	1,984 (1,756-2,263)
35-44	1,139 (1,002-1,314)	2,440 (2,154-2,780)
45-54	2,107 (1,798-2,512)	4,805 (4,093-5,684)
55-64	6,386 (4,818-9,074)	12,559 (9,591-17,435)
65-74	12,076 (8,410-19,391)	19,876 (13,857-32,275)
75-84	19,386 (10,941-53,619)	45,266 (23,961-139,012)
≥85	33,156 (11,691-164,491)	33,298 (12,465-178,502)