Chronic obstructive lung disease “expert system”: validation of a predictive tool for assisting diagnosis

Figures & data

Figure 1 Website design of the COLD_ES, an obstructive lung disease diagnosis-supporting tool.

Notes: Two pages of the questionnaire are shown. The second page of the questionnaire (right) includes possible further questions that are determined by the answers given on the first page of the questionnaire (left).
Abbreviations: COLD, chronic obstructive lung disease; ES, expert system.

Table 1 Cutoff score, risk of COLD, and interpretation implemented in the ES version used in the study (COLD_ES)

Score range	Probability of COLD (%)	Interpretation
ES prediction without lung function test and X-rays
0–75	<30	Unlikely
75–110	<50	Unlikely
110–130	>70	Likely
ES prediction without lung function test and with X-rays
0–50	<20	Unlikely
50–100	<40	Unlikely
100–150	>70	Likely
ES prediction with all data (with or without bronchodilation)
0–60	<10	Virtually excluded
60–115	<40	Unlikely
115–160	>70	Likely
160–200	>85	Very likely

Abbreviations: COLD, chronic obstructive lung disease; ES, expert system.

Table 2 The diagnostic warnings provided by COLD_ES

Warnings	Description
Warning 1	The presence of an accessional dyspnea could be associated with asthma
Warning 2	The presence of a sensitization to inhalant allergens is frequently associated with asthma
Warning 3	A younger age (<45 years) is less frequently associated with COPD, but the presence of a concomitant obstructive pattern always needs further investigation (alpha-1 antitrypsin assessment)
Warning 4	Older age (>60 years) is more frequently associated with COPD, but physiologically reduced functional lung volumes and flows could mimic COPD
Warning 5	The complete reversibility of bronchial obstruction is essential in the differential diagnosis between COPD and asthma. Absent or partial reversibility can be present in both asthma and COPD
Warning 6	Lung function tests are essential for the diagnosis of COLD
Warning 7	Chest X-rays are essential in excluding/confirming lung diseases other than COLD

Abbreviations: COLD, chronic obstructive lung disease; ES, expert system.

Figure 2 Algorithm describing the different steps in the process of validation of the tool.

Abbreviations: COLD, chronic obstructive lung disease; ES, expert system.

Table 3 Consolidated results in 231 unselected samples

Score	Relative risk (%)	Number of patients	COLD	No COLD	% actual	% expected	Concordance	χ^2
0–60	<10	51	5	46	9.8	10	Ok
61–115	<40	67	24	43	35.8	40	Ok
116–160	>70	66	49	17	74.2	70	Ok	0.48
160–200	>85	47	40	7	85.1	85	Ok	0.92
Total		231	118	113

Abbreviation: COLD, chronic obstructive lung disease.