Possible contribution of advanced statistical methods (artificial neural networks and linear discriminant analysis) in recognition of patients with suspected atrophic body gastritis

Table 1 Structured questionnaire containing anagraphic, anamnestic, clinical, and biochemical variables considered as independent variables (input)

Variables	Independent variables (input) levels
1. Sex (2)	Male; female
2. Age1
3. Referred from the Department of… (5)	Hematology, gastroenterology, dermatology, endocrinology, other
4. Presentation symptom (5)	Anemia, GI symptoms/disorders, dermatological symptoms/disorders, endocrinological symptoms/disorders, other
5. Onset of presentation symptom (mo)
6. GI symptoms (4)	Dyspepsia motility-like, dyspepsia ulcer-like, other GI symptoms, absence
7. Neurological symptoms (2)	Yes/no
8. Other symptoms (2)	Yes/no
9. Family history (1st degree relatives) autoimmune diseases (2)	Yes/no
10. Family history (1st degree relatives) for gastric neoplasms (2)	Yes/no
11. Family history (1st degree relatives) for duodenal ulcer or gastric ulcer (3)	No family history, family history for duodenal ulcer, family history for gastric ulcer
12. Association with thyroid disease (2)	Yes/no
13. Association with dermatological disease (2)	Yes/no
14. Association with neoplasms (2)	Yes/no
15. Association with duodenal ulcer or gastric ulcer (2)	Yes/no
16. Association with other diseases not mentioned previously (2)	Yes/no
17. Anemia (3)	No anemia, macrocytic (pernicious) anemia, microcytic (iron-deficiency) anemia
18. Hemoglobin1
19. Mean corpuscular volume (MCV1)
20. Fasting gastrin1
21. Pepsinogen I1
22. Parietal cell antibodies (2)	Presence/absence

GI, gastrointestinal; ABG, atrophic body gastritis;

¹continuous variables.The number of levels of each variable is indicated in the brackets.

Table 2 Performance of ANNs and LDA for diagnosis of ABG

Experiments	ANNs			LDA
	Accuracy (%)	Sensitivity (%)	Specificity (%)	Accuracy (%)	Sensitivity (%)	Specificity (%)
Experiment 1	96.6	97.7	95.5	94.6	95.4	93.2
Experiment 2	98.8	98.4	100	96.8	96	97.5
Experiment 3	98.4	96.8	100	96.8	96	97.5
Experiment 4	91.3	91.7	90.9	88.6	93.2	84.1
Experiment 5	97.7	95.4	100	94.5	94.9	94.2

Table 3 Independent variables identified by LDA as most predictive for the diagnosis of ABG with respective correlation coefficients

Independent variables	Correlation coefficients
Pepsinogen I1	42
Gastrin1	0.4
Age	–0.37
Association with other diseases not previously mentioned2	0.35
Other (not gastrointestinal) symptoms3	0.34
Onset of presentation symptoms (mo)	0.25
Other gastrointestinal symptoms4	0.25
Antibodies against parietal cells1	0.23

¹Serological variables;

²represented in data set by cardiovascular diseases, diabetes type II and other causes of iron-deficiency anemia;

³represented in data set by asthenia, fatigue, and headache;

⁴represented in data set by diarrhea, abdominal pain, and bloating.