SPECTRUM OF PULMONARY INFECTIONS IN CHRONIC KIDNEY DISEASE PATIENTS AND THE ROLE OF VARIOUS DIAGNOSTIC MODALITIES: A SINGLE CENTRE OBSERVATIONAL STUDY.

Introduction:

One of the leading causes of death and suffering in the 21st century is chronic kidney disease (CKD). The prevalence of CKD patients has also been rising, impacting an estimated 843.6 million people globally in 2017. This increase is partly attributable to increased risk factors, including obesity and diabetes mellitus. Although end-stage renal disease (ESRD) patients' mortality has decreased, the Global Burden of Disease (GBD) studies have revealed that CKD has risen to become a significant global cause of mortality. Therefore, it is crucial that CKD be recognized, tracked, and treated and that prevention and therapeutic interventions targeting CKD are consistently carried out globally.

Due to immunological weakness brought on by renal failure, the risk of infection for CKD patients is noticeably higher than that of the general population. The ESRD population has mainly been used to research changes in the host immunological response.  These patients have abnormal polymorphonuclear white blood cell, lymphocyte and monocyte functions, impairing the body's ability to fight infection. Impaired polymorphonuclear leukocyte function is caused by malnutrition, elevated intracellular calcium, iron overload, dialysis membranes, and uremic toxins (i.e., circulating substances that inhibit granulocytes). Diabetes mellitus, a lack of hygiene habits, low socioeconomic status, and the endemic nature of several illnesses in tropical regions are additional risk factors for infection.

In addition, a need to understand the range of organisms present in these regions and the high price of life-saving antimicrobial medications, particularly in those on dialysis and following a kidney transplant, lung infections are frequent and significantly increase the illness burden in people with chronic kidney disease (CKD). If not addressed quickly, respiratory tract infections can be fatal.

In a country like India, where tuberculosis is widespread, diagnosing these diseases can be extremely difficult. Patients with renal disease are more prone to infections, including Pseudomonas, Klebsiella, Pneumocystis carinii, Candida, Mycobacterium tuberculosis, Cytomegalovirus, Influenza, Aspergillus, Nocardia, Staphylococcus, Streptococcus, Anaerobic, Cryptococcal, and MucormycoIsis.

A thorough understanding of the microbiological spectrum would make it easier to begin the proper treatment empirically while waiting for confirmation. In addition, due to the overlap of clinical and imaging characteristics of pulmonary infections with fluid overload and post-COVID-19 sequel, the present explanation of dyspnea in CKD patients could be more precise. Diagnostic techniques include sputum testing for bacterial, fungal, and AFB growth, chest X-rays, HRCT chest, bronchoscopy, and thoracic biopsies.

With this background we conducted this study to observe the spectrum, clinical features, the role of various diagnostic modalities and the outcome of chronic kidney disease patients with pulmonary infection.

Methods:

STUDY DESIGN: Hospital Based Observational Study

STUDY SETTING: Department of Nephrology, Pushpawati  Singhania Hospital and Research institute.

STUDY PERIOD: 2 years [April 2021 to April 2023]

STUDY POPULATION: Patients with CKD and post renal transplant presenting with respiratory infections attending OPD at PSRI Hospital

SAMPLE SIZE:  Bacterial infection is the most common type of respiratory infection reported in various studies. Considering an average of 20% proportion, with 8% absolute error and 95% confidence interval we found the minimum sample size to be 96. Adding up 15% attrition rate we included 113 cases in the present study.

The following simple formula would be used for calculating the adequate sample size in prevalence study. We have included 113 cases in the present study.

SAMPLING TECHNIQUE: Consecutive Convenience sampling

INCLUSION CRITERIA - Pulmonary infection with chronic kidney disease or post-transplant recipients

EXCLUSION CRITERIA - Patients not providing consent for the study

OPERATIONAL DEFINITION:

PULMONARY INFECTION: Constellation suggestive clinical features of fever, cough with or without expectoration or respiratory distress, a demonstrable infiltrate on Chest X ray or CT scan with or without supporting microbiological evidence of infection.

CHRONIC KIDNEY DISEASE: CKD is defined as kidney damage or glomerular filtration rate (GFR) <60 mL/min/1.73 m for 3 months or more, irrespective of cause.

DATA COLLECTION:

Patients underwent a comprehensive clinical evaluation, including physical examination and detailed patient history. The history covered current illnesses, symptoms, prior chest infections, immunosuppression, acute rejection, and antibiotic use. Risk factors such as diabetes and serological status for viruses (COVID-19, hepatitis B and C, CMV) were noted. General laboratory tests, radiographic evaluation, and specialized examinations were conducted to identify the causative organisms. Various laboratory tests, viral tests, and coagulation profile tests were performed. Spontaneously expectorated sputum specimens were examined for bacterial and fungal elements, using Gram stain and Ziehl-Nielsen stain for acid-fast bacilli. Standard criteria for sputum suitability were also applied.

ETHICAL CONSIDERATIONS: All the study participants were provided informed written consent forms before the start of the study. Strict confidentiality about their particulars was maintained throughout the study. The study was approved by Institutional Ethics committee before the start of the study.

STATISTICAL ANALYSIS PLAN:

The data was collected, compiled, and analyzed using EPI info (version 7.2). The qualitative variables were expressed in terms of percentages. The quantitative variables were categorized and expressed in percentages or terms of mean and standard deviations percentages. The difference between the two proportions was analyzed using the chi-square or Fisher exact test. All analysis was two-tailed, and the significance level was set at 0.05.

Results:

The study included 113 cases with an average age of 59.61 ±12.49 years and a male-to female ratio of 2.13:1. Symptoms such as fever (77.88%),cough (71.66%), shortness of breath (67.26%) generalized weakness(48.67%), hemoptysis (1.77%) were observed. 

In addition, imaging findings include nodules in 50.44% of cases, pleural effusion in 38.94% , cavitation in 23.01%, lymph node involvement in 40.71% of cases and a "tree in bud" appearance in 24.78% of cases. 

Of the 113 cases studied, 24.78% were bacterial, 21.24% were viral, , 18.58% were mycobacterial 4.42% were fungal, and 30.97% no organisms were isolated. The diagnostic yield rate for sputum analysis, pleural fluid analysis, bronchoalveolar lavage (BAL) and fine needle aspiration cytology (FNAC) were 17.14%, 35.71% , 64.15%, and 100%,respectively

Conclusions:

The spectrum of pulmonary infection included most commonly bacterial (28%), viral (24%) and mycobacterium (18%) infections. Most common individual organism were found to be mycobacterium tuberculosis(18%) and covid 19 (16.81%). Cough, fever and shortness of breath were the predominant complaints in the present study. CT scans revealed common findings such as nodules, cavitation and lymphadenopathy. The diagnostic yield of sputum analysis was 17.94%, BAL analysis was 64.17%  and  FNAC was 100%. Overall mortality in the study was 8.85%.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.