Introduction

Whether the sensitivity of the BinaxNOW Streptococcus pneumoniae urinary antigen test kit (BinaxNOW), adjusted by some variables including vital signs, laboratory examinations and pneumonia severity, has been decreasing is unknown. The aim of the present study was to investigate whether BinaxNOW sensitivity has decreased recently and to identify the predictors of the BinaxNOW result, including the time trend.

Methods

This prospective cohort study enrolled consecutive patients with pneumococcal community-acquired pneumonia who were hospitalised at Kurashiki Central Hospital from January 2001 to December 2015. Pneumococcal community-acquired pneumonia was defined as positive blood or pleural effusion or sputum culture results. To evaluate the effect of the time trend for the sensitivity of BinaxNOW, time series regression analysis was performed. In addition, predictors of the BinaxNOW result were examined by multivariable analysis using variables such as sex, vital signs, blood tests such as C-reactive protein, albumin, blood urea nitrogen, creatinine, white blood cell count, haematocrit and platelets, antibiotic pre-treatment, bacteraemia, and pneumonia severity, in addition to time trend and seasonality.

Results

A total of 446 patients were included. BinaxNOW sensitivity showed a significant, gradual decrease from 2001 (81.3%) to 2015 (48.7%). On multivariable analysis [odds ratio (95% confidence interval)], bacteraemia [2.516 (1.387–4.561), P = 0.002] was a predictor of a positive BinaxNOW result, whereas male sex [0.467 (0.296–0.736), P = 0.001], white blood cell count [0.959 (0.930–0.989), P = 0.008] and the time trend per year [0.900 (0.859–0.943), P < 0.001] were predictors of a negative BinaxNOW result.

Conclusions

The sensitivity of BinaxNOW decreased over a 15-year period. We should be careful when interpreting BinaxNOW results in daily clinical practice, and the development of a new kit with good sensitivity is anticipated.

Trial registration number

UMIN000004353.

中文翻译：

---

肺炎球菌尿抗原检测诊断肺炎球菌社区获得性肺炎的敏感性的时间趋势：15 年前瞻性队列数据分析

介绍

BinaxNOW肺炎链球菌尿抗原检测试剂盒（BinaxNOW）的敏感性是否通过一些变量（包括生命体征、实验室检查和肺炎严重程度）进行了调整，目前尚不清楚。本研究的目的是调查 BinaxNOW 敏感性最近是否降低，并确定 BinaxNOW 结果的预测因子，包括时间趋势。

方法

这项前瞻性队列研究连续招募了 2001 年 1 月至 2015 年 12 月在仓敷中心医院住院的肺炎球菌社区获得性肺炎患者。肺炎球菌社区获得性肺炎定义为血液或胸腔积液或痰培养结果呈阳性。为了评估时间趋势对 BinaxNOW 敏感性的影响，进行了时间序列回归分析。此外，使用性别、生命体征、血液检测（如 C 反应蛋白、白蛋白、血尿素氮、肌酐、白细胞计数、血细胞比容和血小板、抗生素预- 治疗、菌血症和肺炎严重程度，以及时间趋势和季节性。

结果

共纳入 446 名患者。BinaxNOW 的敏感性从 2001 年 (81.3%) 到 2015 年 (48.7%) 显着逐渐下降。在多变量分析 [优势比（95% 置信区间）] 中，菌血症 [2.516 (1.387–4.561), P  = 0.002] 是 BinaxNOW 结果阳性的预测因子，而男性 [0.467 (0.296–0.736), P  = 0.001] ]、白细胞计数 [0.959 (0.930–0.989), P  = 0.008] 和每年的时间趋势 [0.900 (0.859–0.943), P  < 0.001] 是 BinaxNOW 结果阴性的预测因子。

结论

BinaxNOW 的敏感性在 15 年期间下降。在日常临床实践中解释 BinaxNOW 结果时，我们应该小心，并且预计会开发出具有良好灵敏度的新试剂盒。

试用注册号

UMIN000004353。