Table 2. Univariate and multivariate analyses of odds ratio for an initial low sputum pH (<7.00).

	Univariate analysis			Multivariate analysis
Characteristics	OR	95% CI	P e	OR	95% CI	P f
Age ≥61 yr	8.750	2.100–36.251	0.004	24.535	2.685–224.213	0.005
Male sex	2.291	0.613–8.498	0.320
Smoking history (current/ex-smoker vs. never)	0.938	0.214–4.108	1.000
Use of acid-suppressanta	4.444	1.115–17.497	0.048
Immunocompromisedb	3.600	0.905–14.132	0.096
Extensive lung lesionc	1.697	0.466–6.165	0.514
Presence of cavities	0.300	0.080–1.130	0.105
Sputum appearanced(M vs P)	0.542	0.134–2.219	0.480	0.104	0.010–1.128	0.063
Sputum bacterial load (<2+ vs ≥2+)	3.208	0.877–11.719	0.111

Notes.

CI

confidence interval

OR

odds ratio

^aAcid-suppressant including histamine-2 receptor antagonist and proton pump inhibitor.

^bImmunocompromised; Patients having diabetes mellitus and/or corticosteroid user.

^cExtensive lung lesion; Radiological extent of parenchymal disease over one whole lung.

^dSputum appearance classified by Miller and Jones’ classification.

^eFisher’s exact test.

^f¶ Logistic regression.