Another limitation of the present study that
should be acknowledged is that the subjects recruited
consisted of about 67.89% of the total patients being
treated in our center during the study period and hence
about 32.11% of the data in the target population was
not included for analysis. There is, thus, a possibility
that information presented in these missing subjects
could differ from those acquired in the study subjects
and hence the validity of the present study could
possibly be compromized. A larger scale prospective
study is recommeded to solve this problem but the
expense and time required to conduct such a study
may reduce its interest.