Biology

Bacterial pneumonia is up till now a considerable factor of morbidity and death in patients infected with HIV in the period of antiretroviral combination therapy. The advantage of tobacco withdrawal on the bacterial pneumonia risk has not been measured in such people, who are exposed to other significant threat factors such as HIV-related immunodeficiency. The purpose of the paper was to evaluate the result of tobacco withdrawal on the bacterial pneumonia risk among HIV-infected people. In developed countries, approximately ten percent of the causes of serious morbidity and five percent of the death causes are connected to bacterial pneumonia. Generally, smoking tobacco is recognized as a main risk factor that results in infections of respiratory tract. A noteworthy decrease in the proportion and total numbers of lymphocytes of CD4 count and CD8 count is caused due to the pulmonary infections in smokers mediated by local inflammatory modifications.

The incidence of smoking tobacco is greater among HIV-infected people, normally stated around 50 percent in European partners with HIV, in contrast to 27 percent in the common population of similar age and sexual category. Latest studies have established the consequence of smoking on infections of respiratory tract in people infected with HIV, and encouraged quitting smoking as a main concern. In the study, all patients of the French prospective hospital-based cohort with minimum 2 appointments during the period 2000-2007, without bacterial pneumonia in the initial appointment and with accessible data on consumption of tobacco were included. Status of tobacco smoking is documented at inclusion (tobacco smoking history and present condition) and at every visit (present condition only) with biological, clinical, and therapeutic information. Cases of pneumonia disqualified tuberculosis and mycobacteria. For this study, the bacterial pneumonia that was considered was divided into two groups confirmed (clinical and particular radiological signs collectively by means of a bacteriological evidence) or probable (clinical and particular radiological signs collectively with a winning antibacterial treatment). Status of smoking was described as present smokers, not at all smokers, and past smokers at every follow-up appointment. Depending on the CD4 cell count, 4 classes of immunological conditions were identified 1) less than 200 cellsL, 2) 200-349 cellsL, 3) 350-499 cellsL and 4) greater than or equal to 500 cellsL. Bacterial pneumonia first event time was estimated as the differentiation between the first appointment date in 2000-2007 periods and bacterial pneumonia diagnosis date, or the last appointment date within the analysis. Status of tobacco smoking was considered in the study as a variable of time dependent since quitting attempts and reversions are recurrent in people infected with HIV.

Explanatory variables comprised gender, first visit age, infection of HIV via intravenous drug use and, for variables of time dependent, past AIDS diagnosis, antiretroviral combination therapy, cotrimoxazole prophylaxis, CD4 cell count, plasma HIV RNA, and statin treatment are considered.ResultsIn French prospective hospital-based cohort, 4365 patients were enrolled, who were seen minimum for one time in 2000-2007. Out of 4365 patients, 3336 (76 percent) were involved in the study. 20 percent or 855 individuals had no information available on status of tobacco smoking, 1 percent or 30 patients showed a bacterial pneumonia in the initial appointment and 3 percent or 144 had just one appointment in the period 2000-2007 (Benard et al., 2010). The 1029 not-included individuals did not vary considerably from the available 3336 individuals for the examination with respect to Age forty years old normal in both the groupsProportion of antiretroviral combination therapy treated patients 64 percent vs. 67 percentCategories of HIV transmission heterosexual - 36 percent vs. 30 percent, users that inject drug - 20 percent vs. 21 percent Mean CD4 cell count 449 vs. 450 cells LPlasma HIV RNA 54 percent vs. 50 percent with e 1000 copiesml and Percentage of individuals with an earlier diagnosis of AIDS 21 percent in both the groupsThe not-included individuals were less often male (68 percent when compared to 74 percent in the sample  analysis, p0.001). Amongst the 53 percent (1779 patients) current tobacco smokers included in the study, 16 percent (277 patients) individuals discontinued smoking for a minimum one year during the study period and were regarded as past smokers. Amongst the 12 percent (411 patients) past smokers included in the study, 40 percent (164 patients) deteriorated while follow-up. Amongst the 34 percent (1146 patients) non-smokers included in the study, 4 percent (41 patients) did begin smoking while study period. During 3.3 years of median follow-up and twelve visits of median number, 135 first bacterial pneumonia events were reported. In these 135 cases, 38 percent (51 patients) needed hospitalization. In 104 bacterial pneumonia events identified in smokers, 37 percent (38 patients) needed hospitalization as examined to 50 percent in past and non-smokers. On the whole, 77 percent or 104 bacterial pneumonia episodes were categorized as possible. Of the 23 percent (31 individuals) with recognized bacteria, Streptococcus pneumoniae (twenty two occurrences) was much widespread. Other organisms recognized were Pseudomonas (six occurrences), Staphylococcus aureus (two occurrences) and Haemophilus influenza (one occurrence). 58 percent (78) pneumonia events were identified between the months November-April, that is period of influenza virus outbreaks. Bacterial Pneumonia overall occurrence per 1000 patient-years was 12. The occurrence of bacterial pneumonia per 1000 patient-years when participants were smoking - 15.9 for past smokers  7.9 for non-smokers - 5.9 28.8 among participants with less than 200 CD4 cellsL 16.5 among participants with CD4 cellsL 200 to 349 and 7.7 among participants with greater than or equal to 350 CD4 cellsL.In the multivariate investigation, the relation between CD4 cell count and status of tobacco smoking was not noteworthy. The bacterial pneumonia adjusted hazard was considerably lesser in past smokers when examined with present smokers. It was considerably lesser in non-smokers when compared to present smokers. The bacterial pneumonia hazard was greater when CD4 cell count was less than 200 cellsL, when CD4 cell count was between 200 and 349 mm3 as compared to when CD4 cell count greater than or equal to 500 cellsL.

Bacterial pneumonia hazard did not vary among patients who had CD4 cell count in between 350 and 499 cells L and among patients who had CD4 cell count greater than or equal to 500 cellsL. In the last model, the bacterial pneumonia hazard was also greater among patients with plasma HIV RNA e1000 copiesml (against 1000 copiesml), among intravenous drug users vs. others, among women vs. men, and among patients who has age between 50-60 years and those aged above or equal to 60 years compared to the patients aged less than 30 years.  

DiscussionThe main reason of morbidity in people infected with HIV in the era of antiretroviral combination therapy is bacterial pneumonia. In this study, the bacterial pneumonia occurrence per 1000 patient-years was 12, differentiating with outcomes reported in earlier analysis (8 to 20). The study identified 3 independent bacterial pneumonia risk factor categories non changeable risk factors like gender, age and infection through IDU tobacco smoking, and HIV infection.As earlier reported, people infected through intravenous drug use had a greater risk of bacterial pneumonia than other people. The reason for this may be antiretroviral therapy observance might be poorer in these people.

In addition, daily consumption of cannabis, a common following in this group of patients, may add to this elevated rate of bacterial pneumonia. Women infected with HIV showed a greater bacterial pneumonia risk than men. After changing for bacterial pneumonia major risk factor, this outcome was observed. However, the study was not adjusted for uncertain socio-economic circumstances and belated ability to approach for care, which is much common in females than males and might raise the bacterial pneumonia risk. The study cannot eliminate greater bacterial pneumonia vulnerability in women infected with HIV, but additional research is necessary to discover this assumption.

According to the study, HIV infection raises bacterial pneumonia risk all the way by means of the virus and by means of the associated immunodeficiency. As documented in previous cohort studies, it was monitored that the bacterial pneumonia risk was greater in people who have plasma HIV RNA more than 1000 copiesml. According to one assumption, infection of HIV is related to lungs humoral immunity defects, resulting to an increased vulnerability to infections. Immunodeficiency is normally reported as the main bacterial pneumonia risk factor in individuals infected with HIV. In this study, the occurrence of bacterial pneumonia noticeably raised in people who had CD4 count less than 350 cellsL contrast to those people who had CD4 cell count more than this threshold. Therefore, this highlights the necessity for early diagnosis of HIV and beginning of antiretroviral therapy at greater CD4 cell count levels, so as to conserve cellular immunity.However, there are different methods to prevent bacterial pneumonia in patients infected with HIV.

According to the recent studies, pneumococcal vaccine was efficient for patients infected with HIV. In this analysis, the most normally reported bacterium was Streptococcus pneumonia. In addition, the study reported that 59 percent of episodes of bacterial pneumonia were detected during influenza virus outbreaks period, which is a threat factor for infections of respiratory tract. Influenza vaccination use would also be a significant choice particularly in the environment of epidemic situation although information is missing on its experimental effectiveness and wellbeing in patients infected with HIV.Finally, the study shows the factors that prevent bacterial pneumonia in patients infected with HIV. Initially, for the first time in HIV affected people, the study showed that for minimum 1 year of smoking self-denial, the bacterial pneumonia risk considerably decreased and contrasts to the risk noticed in non smoking people. In the second place, as recorded by the lack of relation between status of tobacco smoking and HIV stimulated immunodeficiency, quitting tobacco smoking is efficient in avoiding bacterial pneumonia, whatsoever the immunodeficiency level. These are proofs for supporting cessation of tobacco smoking in patients infected with HIV. Though, the analysis demonstrated that a great percentage of past smokers relapsed while follow-up, yet after minimum 1 year of quitting. This strengthens the necessity for precise tobacco stopping associations in such people to reduce the bacterial pneumonia trouble.