Multiple Score Comparison: a network meta-analysis approach to comparison and external validation of prognostic scores

Table 5 Group characteristics of the network

g	Scores	Cohorts^a	n	d	Q	df	τ
1	GOLD – ADO	Copenhagen, HUNT, Japan, SEPOC	4323	378	2.8	3	0
2	GOLD – ADO – BODE – BODEupd	Barmelweid, Basque, Galdakao†, Pamplona†, Zaragoza I†	1208	215	15.5	12	0.014
3	GOLD – GOLD (2011) – ADO – BODE – BODEupd	Mar de Plata Argentina, PACECOPD*, Son Espases Mallorca	556	61	10.9	8	0.025
4	GOLD – GOLD (2011) – ADO – BODE – BODEupd – SAFE	COPDgene	4484	337	7.46E-29	0	NA
5	GOLD – GOLD (2011) – ADO – BODEx – DOSE – BAED	Genkols, ICE COLD ERIC, Initiatives BPCO, Sevilla†, Terrassa I†, Terrassa III†, Zaragoza II†	4346	722	48.1	30	0.011
6	GOLD – GOLD (2011) – ADO – BODE – BODEupd – eBODE – BODEx – DOSE – BAED	La Princesa Madrid, Requena II†, Tenerife†, Terrassa II†	845	125	34.5	24	0.014

Abbreviations: g group, n number of subjects, d number of deaths, Q likelihood ratio statistic, df degrees of freedom, τ heterogeneity within the group, GOLD Global initiative for chronic Obstructive Lung Disease, BODE Body mass index, airflow Obstruction, Dyspnoea and severe Exacerbations, BODE upd. BODE updated, ADO Age, Dyspnoea, airflow Obstruction (we use in the our analysis the updated version of the ADO score), e-BODE severe acute exacerbation of COPD plus BODE, BODEx Body mass index, airflow Obstruction, Dyspnoea, severe acute Exacerbation of COPD, DOSE Dyspnoea, Obstruction, Smoking and Exacerbation frequency, SAFE Saint George’s Respiratory Questionnaire (SGRQ) score, Air-Flow limitation and Exercise capacity, B-AE-D Body-mass index, Acute Exacerbations, Dyspnoea
^aCohorts belonging to the ADO or COCOMICS groups are marked with * or † respectively. We notice that for group 4 the value of heterogeneity τau is not available (NA); indeed, that is a singleton group, where we cannot evaluate heterogeneity