Association of Lung cancer with Pneumonia and Chlamydia pneumoniae infection

Introduction: The degree of association and type of causal versus non-causal relationship between pneumonia and lung cancer (LC) are evolving discussions. We reviewed English publications on the degree of association between pneumonia and subsequent LC. Methods: We searched the PubMed database using key words for pneumonia, LC, and chlamydia infection. We selected peer-reviewed studies of patients with pneumonia and LC. Case reports and other literature reviews were excluded from this review. Results: Five studies examined the incidence and/or risk of LC for a total of 415,750 patients, and four studies examined cases with Chlamydia pneumoniae chronic infection at the time of diagnosis of LC for a total of 1,467 patients. The overall risk and/or incidence of LC after pneumonia was from 2.3% to 10% for a median follow-up ranging from 109 days to 4.2 years. Three studies reported current tobacco smoking status, which ranged from 27.7% to 45% among those with LC. A history of prior malignancy was reported in 22.5% of patients with LC. Chlamydia IgA and LC were statistically non-significantly associated regardless of the age of the patients. In one study, Chlamydia HP-60 IgG \u3e 1:50 was associated with significantly increased odds of LC in two respective models (ORs of 1.34 [95% CI 1.06–1.69] and 1.30 [95% CI 1.02–1.67]). A fourth study reported C. pneumoniae IgA \u3e 64 titers to be 58%, 29%, and 5.5% among patients with LC, without LC, and healthy blood donors, respectively. Conclusions: The incidence of LC was reported to range from 2.3% to 10.3% following an episode of pneumonia. There is limited evidence of the association of chronic Chlamydia infection with LC, and Chlamydia could be a causal cofactor of LC

Pulmonary Post-Acute Sequelae of COVID-19

Introduction: Persistent symptoms have been observed in a substantial proportion of survivors of COVID-19 since relatively early in the pandemic. Among these post-acute sequelae of COVID-19 (PASC), respiratory symptoms appear to be the most prevalent. Methods: We conducted a literature review of peer-reviewed publications in English on the clinical and epidemiological features of respiratory PASC in cohorts of 100 or more patients with a follow-up of four weeks or more after acute infection. Included studies reported the prevalence of persistent respiratory symptoms and/or the results of follow-up pulmonary function tests. Results: On our review included 14 studies across eight countries with a total of 2,380 patients. Subacute PASC was reported in 876 patients, and chronic PASC in 1,504 patients. The median age ranged from 44 to 67 years. The most common symptoms observed were fatigue (44%), dyspnea (40%), and cough (22%). Lung disease as a comorbidity was found in 13% of patients on average. Predominance of males was seen in all studies of subacute PASC and six out of eight studies of chronic PASC. The rates of comorbidities for subacute vs. chronic PASC were: hypertension 32% vs. 31%, cardiovascular disease 10% vs. 7%, diabetes mellitus 15% vs. 12%, kidney disease 7% vs. 4%, and lung disease 19% vs. 10%. Conclusion: Respiratory PASC seems to be more predominant as a chronic presentation, more common in male adults, and less common in older persons. Respiratory PASC is most often associated with fatigue, dyspnea, and cough. There was no strong correlation of severity of illness, acute respiratory distress syndrome, or intensive care unit admission with respiratory PASC