How to conduct and write a cross-sectional study

@#<p style="text-align: justify;" data-mce-style="text-align: justify;">Cross sectional study design involves observation of variable/s at a particular point in time. It can be descriptive or analytical. Descriptive cross-sectional study design measures prevalence of disease/traits. Analytical cross-sectional study design evaluates associations between variables. However, it could not establish causality. Doing a cross-sectional study starts with identification of the purpose of the study. This is followed by development of the objectives that should follow the SMART criteria. A dummy table should also be constructed that is based on the objectives of the study so that needed data would not be missed. The next step is defining the population of the study followed by sample size computation which could be done using the Epiinfo™ program. Next, selection of sample population, ideally, using random sampling should be done. This is followed by the development of data collection methods. For cross-sectional studies, questionnaires are frequently used to collect data. 5A’s of questionnaire development should be kept in mind when formulating the questionnaire. In addition, the use of the following should be avoided: double-barreled item; negatively worded item; statements as questions; agreement response anchors; and too few or too many response anchors. Data collection and data analysis will be done next. Analysis of data could also be done using the Epi-info™ program. Descriptive statistics which includes frequency distributions, measures of central tendency and measures of variability provide a description and summary of participants data. Specific type of statistics is determined by the type of variable. For analytical type of crosssectional studies, measure of association could either be Prevalence Ratio (PR) or Odds Ratio (OR). Data independence and type of o utcomedata measured determine what statistical test to utilize in order to test the hypothesis. The STROBE statement should guide the writing of the final paper.</p>

Treatment decisions based on clinical trials

@#The randomized Controlled Trial is the standard design to prove the effectiveness of drugs or other forms of interventions. In this type of clinical research, individuals are randomly assigned (randomization) to either of the two or more groups, one with the intervention the other without the intervention being tested or another intervention. When done properly, it can provide the best evidence of effectiveness

Prevalence and clinico-pathologic features of ALK rearrangement among adult Filipinos with non-small cell lung cancer in a Private Tertiary Care Hospital

Introduction@#With advancements in the understanding of lung cancer biology, targeted therapy has become the rule rather than the exception. Patients with ALK rearrangements are amenable to therapy with Alectinib and other ALK inhibitors, which has been associated with better patient outcomes. While ALK rearrangement should be routinely tested in non-squamous non-small cell lung cancer (NSCLC), the cost and availability of this test is a prohibitive factor, particularly in the Philippine setting.@*Objectives@#This study aimed (1) to determine the prevalence of ALK-rearranged NSCLC among adult Filipino lung cancer patients in St. Luke’s Medical Center (SLMC) from 2016 to 2018 and (2) to determine the clinico-pathologic features of adult Filipinos with ALK-rearranged NSCLC.@*Methodology@#This is a retrospective cross-sectional descriptive study wherein the prevalence of ALK-rearranged NSCLC, detected using fluorescence in-situ hybridization (FISH) or immunohistochemistry (IHC), was determined. Clinical data of patients for whom ALK testing was performed were collected. Hematoxylin and Eosin (H&E) slides were retrieved and reviewed for the presence of certain morphologic features. Patients whose H&E slides cannot be retrieved were excluded from the study. @*Results@#ALK rearrangement was seen in 7.8% (8/103) of tumors submitted for ALK testing. Patients with ALK-rearranged tumors were generally young, light smokers, and presented with advanced clinical stage. Clear cell features and solid pattern were noted in one case and three cases, respectively. However, due to small sample size, further statistical analysis could not be performed to analyze the association of these features with the presence of ALK rearrangement.@*Conclusion@#Despite a small sample size, the prevalence and clinical profile of ALK-rearranged NSCLC in our institution are congruent with those previously described in Western populations. The association of clinical profile and morphologic features with the presence of ALK rearrangement can be further explored in future studies.

Prevalence of CKIT and PDGFRA mutation in gastrointestinal stromal tumors among Filipinos

Background@#Gastrointestinal stromal tumors (GIST) is defined as specific, typically kit (CD117)-positive and CKIT or platelet-derived growth factor receptor alpha (PDGFRA) mutation-driven mesenchymal tumors that can occur anywhere in the GI tract. GIST diagnosis relies heavily on immunohistomorphology. However, with the advent of molecular testing, the classification, diagnosis and targeted-therapy for gastrointestinal mesenchymal tumors have been greatly improved. In the Philippines, molecular testing is not yet readily available as in other countries. The local molecular profile of gastrointestinal stromal tumors is a point of investigation as treatment may be more tailored to the patients’ needs.@*Objective@#This study aims to determine the prevalence of CKIT and PDGFRA mutations among formalin-fixed and paraffin embedded gastrointestinal stromal tumors and other gastrointestinal mesenchymal tumors in St. Luke’s Medical Center – Quezon City.@*Methods@#A retrospective cross-sectional study of formalin fixed and paraffin embedded tumor samples diagnosed as Gastrointestinal Stromal Tumor from January 1, 2009 to December 31, 2017 will be analyzed for KIT and PDGFRA mutations. @*Result@#The epidemiology of GIST remains constant in that mean age group is the 5th to 6th decade, with equal gender distribution, and stomach followed by small bowel are the most common sites. Mutational analysis of the GISTs showed predominantly KIT Exon 11 (47.83%) followed by CKIT Exon 9 (13.04%) and PDGFRA Exon 18 (10.87%). For KIT Exon 11, deletion is the most common mutations followed by point mutations. No mutation is detected in 47.83% of GISTs. @*Conclusion@#Mutational analysis for CKIT-PDGFRA is warranted among GIST patients, as it may significantly influence treatment protocol in our patients.

Programmed Death Ligand 1 (PD-L1) expression and its association with driver mutations among patients with non-small cell lung cancer in a Private Tertiary Care Setting

Objective@#The advent of immunotherapy has significantly changed the treatment and management of patients with advanced non-small cell lung cancer (NSCLC). Prior to initiation of immunotherapy, evaluation of programmed death ligand 1 (PD-L1) expression is required. One factor that affects PD-L1 expression in NSCLC is the presence of oncogenic driver mutations; however, little data on its association is available, especially in the Philippine setting. The study aims to determine the prevalence of PD-L1 expression and its association with driver mutations among patients with non-small cell lung cancer in a private tertiary care hospital in the Philippines.@*Methodology@#The study was undertaken for a period of two years from July 2017-July 2019 at St. Luke’s Medical Center and included 446 NSCLC samples. PD-L1 was evaluated by immunohistochemistry using 22C3 anti-PD-L1 antibody clone, EnVision FLEX visualization system on Autostainer Link 48. Patient demographics and data on driver mutation testing were recorded. Statistical analysis was performed using logistic regression. @*Results@#PD-L1 expression was observed in 273 (61.20%) of 446 cases, 119 (61.20%) of which demonstrated high PD-L1 expression while 154 (34.50%) had low PD-L1 expression. There was no significant association between PD-L1 expression and EGFR mutation, ALK mutation, age, and gender. For histologic type, high PD-L1 expression was significantly associated with adenocarcinoma and non- small cell carcinoma, NOS. @*Conclusion@#The overall prevalence of PD-L1 expression in non-small cell lung carcinoma is 61.20% based on the cases included. Although we did not find an association between PD-L1 expression and EGFR and ALK mutation, our study observed that ALK-mutated NSCLCs have 4.7 odds of having high PD-L1 expression, however, a higher sample size is warranted to truly determine significant association. The outcome of this study may provide help in the stratification of patients and predict those who will benefit from immunotherapy.

Rapid respiratory panel testing for SARS-CoV-2: Experience in a Private Tertiary Hospital

@#SARS-CoV-2 has infected more than 643 million individuals worldwide and accounts for close to 64,950 deaths in the Philippines. Due to COVID-19’s clinical overlap with other diseases and non-specific radiologic findings, its diagnosis rests primarily on laboratory methods, including reverse transcription polymerase chain reaction (RT-PCR) and multiplexed molecular platforms for rapid syndromic testing. Compared to RT-PCR which has a turnaround time of 24 to 72 hours, multiplexed molecular platforms can provide alternative diagnoses to COVID-19 in an average of one hour, providing meaningful data that can impact clinical and resource management when handling acute surge of patients with respiratory symptoms.

Clinical pathway for the management of uninvestigated Dyspepsia among adults in family and community practice: Updated 2021

Background@#Uninvestigated dyspepsia is a common complaint in family practice in the Philippines. Patients usually seek consult due to severity of symptoms which affect their quality of life. The goals of management are short- and long-term symptom control, with reversal of possible underlying mechanisms, achievable through a combination of pharmacologic and non-pharmacologic interventions.@*Objective@#The main objective of this pathway is to guide family physicians and primary care physicians in the assessment, diagnosis and management of adult patients with uninvestigated dyspepsia through a shared decision-making process.@*Method@#This clinical pathway is an update of the PAFP’s Clinical Pathways for the Management of Dyspepsia in Adults (2016). The current panel utilized the ADAPTE method and prioritized reviewing relevant clinical practice guidelines from 2017 to present. Grading of recommendation was achieved through a mixture of strength of available evidence and a consensus from a panel of experts.@*Summary of Recommendations@#The main changes in the recommendations in this update are as follows: symptom-based classification of dyspepsia, screening for anxiety and depression, family and SCREEM assessment; initiation of therapeutic trial for most patients to whom H. pylori testing is not available; extension of initial PPI treatment to 4-8 weeks, consideration of antacids/alginates for immediate symptom relief, consideration of tricyclic antidepressants for non-responders to initial treatment; symptom-based non-pharmacologic advice, consideration of counseling and other psychosocial interventions; empowerment for self-treatment and as-needed therapy for those who have completed the initial treatment regimen@*Dissemination and Implementation@#This guideline shall be disseminated and implemented at the clinic and organizational level. It will be published in the “The Filipino Family Physician” journal, social media platforms and will be disseminated through PAFP local chapters, training institutions and during the national convention. Non-FCM primary care physicians will also be reached through relevant agencies. It shall be included in the references required during training activities and national exams of accredited training institutions, in coordination with the PAFP committee on Residency Training. It shall be incorporated in checklists for compliance in audits and QA cycles, with support from the PAFP committee on Quality Assurance and that on Standards for Family Practice. Feedback on utility and applicability will be actively sought from the intended users and other stakeholders.

Diagnosis and management of Dyslipidemia in family practice

Background@#Atherosclerotic cardiovascular disease (ASCVD) is a top cause of mortality in the Philippines. A known modifiable risk factor for ASCVD is dyslipidemia. Thus, proper diagnosis and management of dyslipidemia in family practice clinic could significantly decrease the burden of cardiovascular disease in the country@*Objectives@#This clinical pathway was developed to guide family and community physicians on the diagnosis and management of dyslipidemia.@*Methods@#To develop evidence -based recommendations, the authors searched for the latest guidelines of reputable international and local societies. They also searched PubMed using the terms “dyslipidemia”, “diagnosis”, “therapeutics”, “family” and “community medicine”. The more rigorous meta-analysis of clinical trials and observational studies were prioritized over lowquality trials in the formulation of the recommendations.@*Recommendations@#Thorough ASCVD risk assessment for all adults should be done during initial visit in family practice. The physician should review patient’s present medication; probe regarding lifestyle habits; conduct complete physical examination; use family assessment tools; and assess risk for ASCVD using calculators or risk factor counting method. For patients ≥ 45 years old and all adult patients regardless of age at increase ASCVD risk the following should be requested: lipid profile, urinary albumin- creatinine ratio/ urinary dipstick test, alanine transaminase (ALT), 12-lead electrocardiography (12-L ECG) and fasting blood sugar (FBS). During subsequent visits, re-assessment of ASCVD risk; checking compliance to non-pharmacologic intervention; and review of medication adherence and adverse effects should be performed. Repeat measurement of lipid profile should be done 6-8 weeks after initiation of statin therapy; 8-12 weeks after dose adjustment; and biannually for patients with controlled lipid levels. For individuals on statin therapy who have already achieved their low-density lipoprotein cholesterol (LDL-C) goal, compute for non- high density lipoprotein cholesterol (non-HDL C). Repeat ALT 6-8 weeks after initiation of statin therapy for those at high risk of statin-induced liver injury. Request creatine kinase (CK) if with development of muscle symptoms while on statin therapy. For primary prevention, start low-moderate intensity statins for following: individuals with diabetes mellitus (DM) Type 2 without ASCVD; individuals with mild-moderate chronic kidney disease (CKD); and individuals without ASCVD aged ≥ 45 years old with LDL -C ≥ 130 mg/dl AND with ≥ 2 risk factors. Start high intensity statins for individuals diagnosed with Familial Hypercholesterolemia. Give high intensity statins as secondary prevention for individuals with established ASCVD. For individuals with ASCVD on maximally tolerated statin therapy not meeting target LDL-C, ezetimibe could be added to their regimen. Low saturated fat diet rich in fruits and vegetable; regular exercise; and smoking cessation should be advised for all adult patients. The physician should also engage other family members to adopt healthy lifestyle. Formation of a community-based lifestyle intervention program to reduce cardiovascular risk should also be supported by the family physician.@*Implementation@#Adherence to pathway recommendations that are graded as either A-I, A-II or B-I is strongly advised. However, the authors also recommend using sound clinical judgment and patient involvement in the decision making before applying the recommendations.

Programmed Death Ligand 1 (PD-L1) expression and its association with clinicopathologic profile in patients with non-small cell lung cancer in a Philippine Tertiary Medical Center

Introduction@#The current management of advanced non-small cell lung cancer (NSCLC) includes the characterization of Programmed Death Ligand-1 (PD-L1) expression for potential immune checkpoint inhibitor treatment. There is currently no available data regarding the patterns of PD-L1 expression in NSCLC, as well as their association with clinicopathologic profile in Filipino patients.@*Methodology@#Clinicopathologic characteristics of 187 consecutive NSCLC clinical samples with PD-L1 testing using the clone 22C3 pharmaDx kit were collected. The presence of stromal tumor-infiltrating lymphocytes (TILs) were assessed in hematoxylin and eosin-stained slides. PD-L1 expression on tumor cells (TC) and stromal TILs were evaluated. @*Results@#Of the 187 cases, there were 112 males and 75 females. The mean age at diagnosis was 66.4 years old (32-92 years old). It is composed of 131 cases of Adenocarcinoma, 15 Squamous cell carcinoma, 4 Adenosquamous carcinoma, 32 Non-small cell carcinoma, not otherwise specified, 3 poorly differentiated malignancy, 1 Large cell carcinoma, and 1 Mucinous carcinoma. Specimen types included 17 pleural fluid cell blocks, 60 tumor cell block samples, and 110 tissue biopsies. Tumor cell PD-L1 expression was identified in 59.1% of the 110 tissue biopsies. PD-L1 TPS for histologic specimens are as follows: TPS >50%, TPS 1-49%, and TPS <1% were observed in 23.6%, 35.5%, and 40.9% in our lung cancer cohort, respectively. Of the 77 cytology specimens, 50.6% presented with TC PD-L1 expression. TPS for this subgroup include: 49.4% with no PD-L1 expression, 35.1% with low PD-L1 expression, and 15.6% showing high PD-L1 expression. PD-L1 expression on TC did not correlate with age, sex, or histology for both specimen type subgroups. Stromal tumor-infiltrating lymphocytes were noted in 74.5% of tissue biopsies. Tumor cell block samples did not demonstrate stromal TILs. For tissue biopsies, female gender and TPS 1-49% were more likely to have <50% PD-L1 expression on TILs.@*Conclusion@#Overall TC PD-L1 expression was observed in more than half (55.6%) of NSCLC patients in our cohort. The prognostic value of PD-L1 and clinical response to immune checkpoint inhibitors in the Filipino population needs to be further investigated.