Excel program for figures

The statistical analysis of data was done using the excel program for figures and SPSS (SPSS, Inc., Chicago, IL) version 16. The description of the data was done in the form of mean ±SD for quantitative data and frequency and proportion for qualitative data. The analysis of the data was done to test statistical significant difference between groups. The primary endpoint was to determine if there was any difference in outcome in terms of postoperative complications (wound infection, collection necessitating drainage and reoperation) and hospital stay in cases of cholecystectomy for acute calculous cholecystitis with and without prophylactic drainage. For quantitative data, independent t-test was used to compare between two groups. For qualitative data Chi-square test was used. Risk adjusted analysis was done using the binary logistic regression for incidence of complications as a dependent variable and linear regression analysis for hospital stay as a dependent variable to determine the risk factors which affected the outcome if present. P < 0.05 was considered significant.