Diagnostic accuracy of tests for Helicobacter pylori in an Alaska Native population.

AIM: To evaluate the accuracy of two non-invasive tests in a population of Alaska Native persons. High rates of Helicobacter pylori (H. pylori) infection, H. pylori treatment failure, and gastric cancer in this population necessitate documentation of infection status at multiple time points over a patient's life. METHODS: In 280 patients undergoing endoscopy, H. pylori was diagnosed by culture, histology, rapid urease test, (13)C urea breath test (UBT), and immunoglobulin G antibodies to H. pylori in serum. The performances of (13)C-UBT and antibody test were compared to a gold standard defined by a positive H. pylori test by culture or, in case of a negative culture result, by positive histology and a positive rapid urease test. RESULTS: The sensitivity and specificity of the (13)C-UBT were 93% and 88%, respectively, relative to the gold standard. The antibody test had an equivalent sensitivity of 93% with a reduced specificity of 68%. The false positive results for the antibody test were associated with previous treatment for an H. pylori infection [relative risk (RR) = 2.8]. High levels of antibodies to H. pylori were associated with chronic gastritis and male gender, while high scores in the (13)C-UBT test were associated with older age and with the H. pylori bacteria load on histological examination (RR = 4.4). CONCLUSION: The (13)C-UBT outperformed the antibody test for H. pylori and could be used when a non-invasive test is clinically necessary to document treatment outcome or when monitoring for reinfection.

Alaska sentinel surveillance for antimicrobial resistance in Helicobacter pylori isolates from Alaska native persons, 1999-2003.

BACKGROUND: Previous studies in Alaska have demonstrated elevated proportions of antimicrobial resistance among Helicobacter pylori isolates. MATERIALS AND METHODS: We analyzed H. pylori data from the Centers for Disease Control and Prevention (CDC)'s sentinel surveillance in Alaska from July 1999 to June 2003 to determine the proportion of culture-positive biopsies from Alaska Native persons undergoing routine upper-endoscopy, and the susceptibility of H. pylori isolates to metronidazole [minimum inhibitory concentration (MIC) of > 8 g metronidazole/mL), clarithromycin (MIC > or = 1), tetracycline (MIC > or = 2) and amoxicillin (MIC > or = 1)] using agar dilution. RESULTS: Nine-hundred sixty-four biopsy specimens were obtained from 687 participants; 352 (51%) patients tested culture positive. Mean age of both culture-positive and culture-negative patients was 51 years. Metronidazole resistance was demonstrated in isolates from 155 (44%) persons, clarithromycin resistance from 108 (31%) persons, amoxicillin resistance from 8 (2%) persons, and 0 for tetracycline resistance. Metronidazole and clarithromycin resistance varied by geographic region. Female patients were more likely than male subjects to show metronidazole resistance (p < .01) and clarithromycin resistance (p = .05). CONCLUSIONS: Resistance to metronidazole and clarithromycin is more common among H. pylori isolates from Alaska Native persons when compared with those from elsewhere in the USA.

Prospective evaluation of a first trimester screening program for Down syndrome and other chromosomal abnormalities using maternal age, nuchal translucency and biochemistry in an Australian population.

BACKGROUND: A combination of maternal age and ultrasound assessment of the nuchal translucency (NT) has been used in the first trimester to screen for chromosomal abnormality. In the United Kingdom, the addition of NT screening was shown to be beneficial. AIMS: To report the sensitivity of combined first trimester biochemistry and ultrasound screening for Down syndrome in an Australian private practice specialising in obstetric ultrasound. METHODS: A prospective study in a private obstetric ultrasound practice. Over 22 months, 2121 patients were screened and data was analysed for sensitivity (detection) and false positive rates for all chromosome abnormalities. RESULTS: There were 17 chromosomal abnormalities, five of which were Down syndrome. Using maternal age alone or age and biochemistry, four of the Down syndrome cases were detected for a 29 and 19% false positive rate, respectively. Using age and NT or age, NT and biochemistry, all the Down syndrome cases were detected, for a false positive rate of 5.7 and 7.2%, respectively. The difference in detection rates for Down syndrome or other chromosomal abnormalities, using the four screening methods, did not reach statistical significance. However, the false positive rates in screening methods without ultrasound to assess the NT was significantly higher (P < 0.01). CONCLUSIONS: A combination of maternal age, NT and maternal serum biochemistry gives a high detection rate for both trisomy 21 and other chromosomal abnormalities. Down syndrome screening using either maternal age alone or age in combination with first trimester biochemistry conferred screen positive rates significantly higher than when combined with NT.

Early radiographic and clinical features associated with bronchiectasis in children.

Bronchiectasis among children living in developing regions is associated with respiratory infections during early childhood, but specific risk factors that precede childhood bronchiectasis are not fully characterized. We hypothesized that severe respiratory syncytial viral (RSV) infection in infancy would increase the risk of bronchiectasis among Alaska Native children in rural Alaska. This was a follow-up cohort study of a 1993-1996 case-control study of RSV-hospitalized case patients and their controls. For each 5-8-year-old former case-patient and control subject, we reviewed medical records, interviewed parents, performed physical examinations and spirometry, collected sera, and analyzed all historical chest radiographs. Ten (11%) RSV cases and 10 (9%) controls had radiographic evidence of bronchiectasis. The mean age at radiographic diagnosis of bronchiectasis was 3.3 years (range, 1.2-6.1 years). Children were more likely to develop bronchiectasis if their chest radiographs, when they were < 2 years of age, showed lung parenchymal densities (RR = 3.9, P < 0.013), persistent parenchymal densities > 6 months' duration (RR = 3.0, P = 0.02), or infiltrates on multiple episodes (test for trend, P = 0.003). Radiographic features of hyperinflation and atelectasis among children < 2 years old were not associated with eventual bronchiectasis. A single severe infection with RSV alone did not predispose Alaska Native infants to bronchiectasis. Childhood bronchiectasis was associated with lung and hence airway injury, manifested on radiographs by parenchymal densities or "pneumonia" rather than by hyperinflation or atelectasis.

The loss rates for invasive prenatal testing in a specialised obstetric ultrasound practice.

OBJECTIVES: To establish the spontaneous miscarriage rate and compare it with the procedure related miscarriage rate for amniocentesis and chorionic villus sampling (CVS) by experienced operators. DESIGN: Retrospective audit over a two-year period of all patients having a consultation for prenatal diagnosis before 12 weeks gestation. SETTING: A specialised obstetric and gynaecological ultrasound practice. POPULATION: A total of 2366 patients, mostly over 35 years of age. METHODS: Between 1 July 1995 and 30 June 1997, all patients having a prenatal consultation decided between amniocentesis, CVS or no invasive testing. The CVS was performed either transabdominally or transcervically, depending on the position of the uterus and placenta. MAIN OUTCOME MEASURES: Delivery, termination of pregnancy for chromosomal abnormality or miscarriage. RESULTS: Over the two-year period, 2366 patients had a prenatal consultation and outcome data were available for all but 53 patients. After consultation, 346 patients decided not to have any prenatal testing and 29 (8.4%) of these had a spontaneous miscarriage. Amniocentesis was requested by 839 patients; however 10 miscarried before the scheduled procedure. After the amniocentesis, there were 13 terminations for chromosomal abnormality and three miscarriages. CVS was requested by 1128 patients; however, 23 miscarried before the scheduled procedure. Transabdominal CVS was performed in 665 patients, transcervical in 416 and in 24 cases the documentation of the method used was unclear. Eleven patients miscarried after the transabdominal CVS (1.65%) compared with nine patients miscarrying after the transcervical CVS (2.16%), which was not statistically significant (p = 0.27). CONCLUSION: In the group studied, the spontaneous miscarriage rate from nine weeks gestation is very high (8.4%). The procedure-related loss rate from amniocentesis was less than 1 in 280. Transabdominal CVS appears to have a lower fetal loss rate than transcervical CVS, but much larger numbers are needed to prove this.