Table 3: Distribution of variable values and readmissions (population size is 69,984).

Variable Number of
encounters
% of the
population
Readmitted
Number of encounters% in group

HbA1c
 No test was performed 57,08081.6%5,3429.4%
 Result was high and the diabetic medication was changed4,0715.8%3618.9%
 Result was high but the diabetic medication was not changed2,1963.1%1667.6%
 Normal result of the test6,6379.5%5908.9%
Gender
 Female37,23453.2%3,4629.3%
 Male32,75046.8%2,9979.2%
Discharge disposition
 Discharged to home44,33963.4%3,1847.2%
 Otherwise25,64536.6%3,27512.8%
Admission source
 Admitted from emergency room37,27753.3%3,5639.6%
 Admitted because of physician/clinic referral22,80032.6%2,0328.9%
 Otherwise9,90714.2%8468.5%
Specialty of the admitting physician
 Internal Medicine10,64215.2%1,0449.8%
 Cardiology4,2136.0%3097.3%
 Surgery3,5415.1%2848.0%
 Family/general practice4,9847.1%4929.9%
 Missing or unknown33,64148.1%3,2379.6%
 Other12,96318.5%1,0938.4%
Primary diagnosis
 A disease of the circulatory system (icd9: 390–459, 785)21,41130.6%2,1299.9%
 Diabetes (icd9: 250.xx)5,7478.2%5299.2%
 A disease of the respiratory system (icd9: 460–519, 786)9,49013.6%7107.5%
 Diseases of the digestive system (icd9: 520–579, 787)6,4859.3%5328.2%
 Injury and poisoning (icd9: 800–999)4,6976.7%52411.2%
 Diseases of the musculoskeletal system and connective tissue (icd9: 710–739)4,0765.8%3548.7%
 Diseases of the genitourinary system (icd9: 580–629, 788)3,4354.9%3139.1%
 Neoplasms (icd9: 140–239)2,5363.6%2399.4%
 Other 12,10717.3%1,1299.3%
Race
 African American12,62618.0%1,1168.8%
 Caucasian52,30074.7%4,9439.5%
 Other 3,1384.5%2568.2%
 Missing1,9202.7%1447.5%
Agea
 30 years old or younger1,8082.6%1126.2%
 30–60 years old 21,87131.3%1,6147.4%
 Older than 6046,30566.2%4,73310.2%

Age (numeric)meanmedian1st Qu.3rd Qu.

 Age in years64.9675577
Time in hospital
 Days between admission and discharge (1–14)4.3326

After the preliminary analysis of the relationship between age and the logistic transformation of the readmission rate. See Figure 2.