Table 4. Negative binomial Regression analysis: Participant characteristics and consultation behaviour.

Variable*	IRR	95% CI	p-value
Pre-questionnaire GP visits
Linear term	1.084	1.064–1.104	< .0005
Squared term	0.999	0.998–0.999	< .0005
Total symptoms	1.094	1.043–1.147	< .0005
Number of comorbidities	1.151	1.089–1.216	< .0005
Gender (ref. male)	1.082	0.955–1.226	.215
Age group (ref. 50–59 years)
60–69	1.128	0.944–1.347	.185
70–79	1.315	1.047–1.653	.019
80+	1.442	1.081–1.924	.013
Employment (ref. full-time)
Part-time	0.686	0.532–0.884	.004
Retired	0.833	0.687–1.011	.065
Other	0.842	0.650–1.090	.192
Domestic (ref. married)
Single	1.082	0.837–1.398	.547
Divorced/separated	0.959	0.805–1.144	.644
Widowed	1.298	1.060–1.589	.012
Living with partner	1.115	0.877–1.416	.374
Highest qualification (ref. none)
GCSE/O-level	0.933	0.786–1.109	.432
A-level	0.786	0.629–0.982	.034
Degree	0.924	0.762–1.119	.418
MA, PhD	1.076	0.788–1.469	.646
Vocational	0.949	0.796–1.130	.555
Severity breathlessness	0.965	0.937–0.993	.015

*Site not shown; IRRs ranged from 1.007 (95% CI [0.769, 1.320]) to 1.549 (95% CI [1.179, 2.035]). Parameter α (to model additional dispersion in negative binomial model) estimated as 0.289 (95% CI [0.229, 0.365]).