Bioestatística e epidemiologia: perguntas que você sempre quis fazer, mas nunca teve coragem / Biostatistics and epidemiology: questions you always wanted to ask but never had the courage to

Dando continuidade aos artigos da série "Perguntas que você sempre quis fazer, mas nunca teve coragem", que tem como objetivo responder e sugerir referências para o melhor entendimento das principais dúvidas estatísticas levantadas por pesquisadores da área da saúde, este terceiro artigo aborda o contexto epidemiológico. Neste contexto, foram diferenciadas as principais medidas como prevalência, incidência, Odds Ratio (OR), Risco Relativo (RR), Razão de Prevalência (RP) e Hazard Ratio (HR), foi esclarecido o uso de análises por intenção de tratar e análise por protocolo, e também discutidos alguns dos termos comumente utilizados e pouco compreendidos como tipo de amostra, nível de evidência, relevância clínica e estatística, entre outros. (AU)

Continuing the series of articles "Questions you always wanted to ask but never had the courage to," which aims to answer key statistical questions raised by health researchers and suggest references for a better understanding, this third article addresses the epidemiological context. In this context, important measures such as prevalence, incidence, odds ratio (OR), relative risk (RR), prevalence ratio (PR) and hazard ratio (HR) were differentiated; the use of intention-to-treat analysis and per-protocol analysis was clarified; and some terms commonly used and poorly understood were discussed, such as type of sample, level of evidence, clinical and statistical relevance, among others. (AU)

Eradication Rates of 10-day Sequential Therapy for Helicobacter pylori: Results of an 8-year Prospective Study Conducted at a Tertiary Korean Hospital / 대한소화기학회지

BACKGROUND/AIMS: The Helicobacter pylori (H. pylori) eradication rate of standard triple therapy is unsatisfactory in Korea, and sequential therapy (SQT) has been suggested to be a practical first-line alternative regimen. The aim of this prospective study was to document changes in annual eradication rates of SQT. METHODS: A total of 983 H. pylori-positive subjects were enrolled from 2010 to 2018 and their data were subjected to intention-to-treat (ITT) and per-protocol (PP) analysis. All subjects received 10-day sequential therapy consisting of 40 mg esomeprazole and 1 g amoxicillin b.i.d for 5 days followed by 40 mg esomeprazole b.i.d, 500 mg clarithromycin b.i.d and 500 mg metronidazole t.i.d for 5 days. The 13C-urea breath test, rapid urease test (CLO test®), and histology were used to confirm eradication. Compliance and side effects were also investigated. RESULTS: ITT and PP eradication rates of SQT were 69.9% (687 of 983) and 87.1% (657 of 754), respectively. The annual eradication rate of ITT remained consistent over the 8-year study period (p for trend=0.167), whereas PP analysis showed the eradication rate increased (p for trend=0.042). The overall adverse event rate for SQT was 41.7% (410 subjects). CONCLUSIONS: Despite high antibiotic resistance rates in Korea, the eradication rate of SQT did not decrease over the 8-year study period.

Double-Blind Placebo-Controlled Randomized Clinical Trial of Topiramate Add-On Therapy in Medically Intractable Partial Epilepsies

BACKGROUND: To evaluate the efficacy and safety of topiramate (TPM) as add-on therapy in medically intractable partial epilepsies. METHODS: This study was a multicenter double-blind placebo-controlled randomized parallel group trial consisting of 12 weeks of baseline phase, 10 weeks of titration phase, and 8 weeks of maintenance phase. The primary efficacy variable was the median seizure frequency reduction rate(MSFRR) and the other efficacy variables included responder rate, seizure free rate, and global evaluations by the patient and the physician. The patient should have partial epilepsies refractory to the maximally tolerable doses of one to two antiepileptic drugs(AEDs) and should have at least two or more episodes of clinical seizures every 4 weeks during the baseline phase. The target dose of study drugs was 600mg/day. The study drug was started at the initial dose of 50mg/day and increased by 50mg/day every week until 400mg/day was reached. Thereafter, the dose was increased by 100mg weekly over next two weeks. RESULTS: A total of 177 patients were randomized into TPM group(n=91) and placebo (PLC) group (n=86). Baseline median seizure frequencies were 5.60 episodes/4 weeks in TPM group and 5.59 episodes/4 weeks in PLC group. Among those who were randomized, 158 patients (TPM: 78 patients, PLC: 80 patients) were available for efficacy measurement by intention-to-treat analysis. The MSFRR was 63.6% for TPM and 17.9% for PLC, which was highly in favor of TPM (p=0.0001). The responder rate was 59.0% for TPM and 23.8% for PLC (p=0.001). Thirteen of 78 patients (16.7%) taking TPM became seizure free compared to 2 of 80 patients (2.5%) taking PLC (p=0.004). The global evaluation by the patient and the physician greatly favored TPM (p=0.001, p=0.001). The incidence of adverse events(AE) was higher in TPM(81.3%) than PLC (48.9%) with CNS-related AE being the most frequent. Among individual AE, anorexia (20.9%) and abdominal pain or discomfort (20.9%) were the most common AE in TPM group. AE precipitated early drop out in 7 patients taking TPM (7.6%) and 3 patients taking PLC(3.5%). No serious AE were observed. CONCLUSIONS: TPM was highly effective and safe as add-on therapy in medically intractable partial epilepsies. Slower titration of TPM seems to decrease the drop-out rate but the incidence of AE was still high. The AE profile of TPM in Asians was different from that in Caucasians.