Background: Infections of respiratory tract are perhaps the most common human aliments. Lower respiratory tract infections in diabetes are common disorder and more often they co-exist. At present an epidemic of DM is ongoing both in developed and developing countries. This study was conducted to analyze clinical impact of  DM on lower respiratory tract infections.

Methodology: This study was carried out in the department of TB and chest disease, P.D.U. medical college and hospital at rajkot during August 2013 to august 2015 to study the association between DM and lower respiratory tract infections. In this study total 50 patients of all ages and either sex were selected randomly from patients admited in TB and chest ward.

Results: The present study was carried out on 50 patients having DM with LRTI. The commonest age group affected was of 40-60 years (62%). Males were affected more than females with male: female ratio was 1.9:1. 72% patients are from rural area with 60% patients are from lower socioeconomic status and 36% patients are from middle socioeconomic status. Cough and fever were present in almost all patients (96%). Besides that anorexia, weight loss, breathlessness, chest pain and hemoptysis were observed in 48%, 42%, 28%, 28% and 12% respectively. Duration of DM was less than 1 year and 1-5 years in 30% and 42% patients respectively. 10% patients had controlled DM while 70% had uncontrolled DM. 50% patients were on OHA, 24% were on insulin and 6% were on both OHA and insulin, while 20% were first time detected as diabetic. Among all organisms causing lower respiratory tract infection, mycobacterium tuberculosis was the most common organism isolated in about 44% of patients. No organism was isolated in 32% patients. Radiologically, 48% patients had moderately advanced lesion, 40% had far advanced lesion and 12% had only minimal lesion. 40% patients had unilateral involvement while 60% had bilateral involvement. 80% patients had exudative lesion, 50% had cavitatory lesions while 16% had nodular lesion.

Conclusions:  Study revealed that lower respiratory tract infections in diabetics is more common than non diabetes. DM patients with age more than 50 years, duration more than 4 years and uncontrolled DM status have more chances of developing pulmonary infection and other DM related complication. Mycobacterium tuberculosis is the most common isolated pathogen   among DM with LRTI patients. Patients of DM with pulmonary TB   have higher sputum positive grading. Radiologically, moderate to far advanced lesions are more common with predominant exudative or mixed variety. There are higher chances of lower lobe involvement in DM patients. H1N1 pneumonia has higher mortality in diabetes than  non-diabetes.