Table 2

Subanalysis of the ICD-9 codes for idiopathic pulmonary fibrosis clinical syndrome (using the ONS data set)

ICD-9 code 515	Raw deaths	Crude mortality rate (95% CI) per 100 000 person-years	Mutually adjusted rate ratios (95% CI)
Calendar period
1979–1983	1923	0.77 (0.74 to 081)	1.0
1984–1988	2687	1.08 (1.04 to 1.12)	1.31 (1.23 to 1.39)
1989–1994	3526	1.16 (1.12 to 1.20)	1.35 (1.28 to 1.43)
1995–2000	4853	1.57 (1.53 to 1.62)	1.76 (1.67 to 1.89) p for trend<0.0001
Sex
Male	7663	1.42 (1.39 to 1.45)	1.0
Female	5326	0.93 (0.91 to 0.96)	0.43 (0.42 to 0.45) p<0.0001
Age group (years)
≤54	571	0.07 (0.06 to 0.08)	0.02 (0.022 to 0.026)
55–59	480	0.80 (0.73 to 0.88)	0.28 (0.25 to 0.31)
60–64	928	1.63 (1.53 to 1.74)	0.57 (0.53 to 0.62)
65–69	1482	2.80 (2.67 to 2.95)	1.0
70–74	2220	4.81 (4.62 to 5.02)	1.75 (1.64 to 1.87)
75–79	2738	7.66 (7.37 to 7.95)	2.86 (2.69 to 3.05)
80–84	2476	10.80 (10.39 to 11.24)	4.22 (3.95 to 4.50)
≥85	2094	12.69 (12.16 to 13.25)	5.25 (4.90 to 5.61) p for trend <0.0001

ICD-9 code 516.3	Raw deaths	Crude mortality rate (95% CI) per 100 000 person-years	Rate ratios (95% CI)
Calendar period
1979–1983	1935	0.78 (0.75 to 0.82)	1.0
1984–1988	3201	1.28 (1.24 to 1.33)	1.57 (1.49 to 1.67)
1989–1994	5126	1.68 (1.64 to 1.73)	2.02 (1.92 to 2.13)
1995–2000	6727	2.18 (2.13 to 2.23)	2.55 (2.43 to 2.69) p for trend <0.0001
Sex
Male	10545	1.96 (1.92 to 1.99)	1.0
Female	6444	1.13 (1.10 to 1.16)	0.42 (0.40 to 0.43) p<0.0001
Age group (years)
≤54	828	0.10 (0.09 to 0.11)	0.02 (0.018 to 0.021)
55–59	897	1.50 (1.41 to 1.60)	0.30 (0.28 to 0.33)
60–64	1567	2.75 (2.62 to 2.89)	0.56 (0.53 to 0.60)
65–69	2542	4.83 (4.65 to 5.03)	1.0
70–74	3318	7.23 (6.99 to 7.49)	1.52 (1.45 to 1.60)
75–79	3620	10.16 (9.83 to 10.49)	2.19 (2.08 to 2.31)
80–84	2614	11.41 (11.0 to 11.85)	2.56 (2.42 to 2.70)
≥85	1603	9.72 (9.25 to 10.21)	2.29 (2.15 to 2.44) p for trend<0.0001

All the mortality rate ratios are mutually adjusted for all other variables in the table.
ICD, International Classification of Diseases.