Table 5. PPV and sensitivity of the algorithms to identify AECOPD including only patients for whom additional information was available from their GP questionnaire.

Algorithm (inclusive definitions)	N events identified in the CPRD	N events confirmed by reference standard	PPV (95% CI)	N events identified in the CPRD in last year	N extra events identified by GPs in last year	Sensitivity (95% CI)
1.OCS prescription	367	265	72.2 (66.5–77.9)	44	150	22.7 (16.1–29.2)
2.Antibiotic prescription	2245	1376	61.3 (58.3–64.3)	123	71	63.4 (55.4–71.4)
3.OCS and antibiotic prescription	251	200	79.7 (73.5–85.8)	36	158	18.6 (12.4–24.7)
4. Symptoms definition	83	53	63.9 (52.7–75.0)	4	190	2.1 (0.1–4.0)
5. Symptoms definition and OCSPrescription	50	47	94.0 (88.0–100.0)	4	190	2.1 (0.1–4.0)
6. Symptoms definition and antibiotic prescription	36	34	94.4 (86.8–100.0)	3	191	1.6 (0.1–3.2)
7. Symptoms definition and OCS & antibiotic prescription	31	31	100.0 (88.8–100.0)	3	191	1.6 (0.1–3.2)
8. LRTI code	693	574	82.8 (78.8–86.9)	48	146	24.7 (18.8–30.7)
9. LRTI code and OCS prescription	621	525	84.5 (80.6–88.5)	40	154	20.6 (15.2–26.0)
10. LRTI code and antibiotic prescription	142	132	93.0 (88.3–97.6)	24	170	12.4 (7.8–16.9)
11. LRTI code and OCS & antibiotic prescription	129	119	92.2 (87.1–97.4)	21	173	10.8 (6.7–15.0)
12. AECOPD code	350	344	98.3 (96.9–99.6)	52	142	26.8 (19.7–33.9)
13. AECOPD code and OCS prescription	236	234	99.2 (98.1–100.0)	36	158	18.6 (12.4–24.7)
14. AECOPD code and antibiotic prescription	155	152	98.1 (96.0–100.0)	33	161	17.0 (10.8–23.2)
15. AECOPD code and OCS & antibiotic prescription	140	138	98.6 (96.8–100.0)	30	164	15.5 (9.7–21.2)

Antibiotics = selected antibiotics with clinical application in management of AECOPD

OCS = oral corticosteroids specific to AECOPD management