Validity and reliability of the COVID-19 symptom index, an instrument evaluating severity of general and otolaryngological symptoms

Abstract

Background

There is no clinical instrument evaluating symptoms of COVID-19.

Objective

To develop a clinical instrument for evaluating symptoms of COVID-19 mild-to-moderate forms.

Methods

COVID-19 patients were recruited from EpiCURA Hospital (Belgium). They completed the COVID-19 Symptom Index (CSI) twice to assess the test-retest reliability. The internal consistency was evaluated with Cronbach’s alpha. CSI was completed by healthy subjects to assess the internal validity. Patients completed CSI 6 weeks after the COVID-19 resolution to evaluate the responsiveness to change.

Results

Ninety-four COVID-19 patients and 55 healthy individuals completed the evaluations. Symptoms associated with the higher severity score were fatigue, headache and myalgia. The Cronbach’s alpha value was 0.801, indicating high internal consistency. The test-retest reliability was adequate (r_s = 0.535, p = .001). The correlation between CSI total score and SNOT-22 was high (r_s = 0.782; p < .001), supporting a high external validity. COVID-19 patients reported significant higher CSI score than healthy individuals, suggesting an adequate internal validity. The mean CSI significantly decreased after the COVID-19 resolution, supporting a high responsiveness to change property.

Conclusion and significance

The CSI is a reliable and valid patient reported outcome questionnaire for the evaluation of symptom severity of COVID-19 patients.

Chinese abstract

背景：目前尚无可用于评估COVID-19症状的临床仪器。

目的：开发一种评估轻度至中度COVID-19症状的临床工具。

方法：从比利时EpiCURA医院招募COVID-19患者。他们两次完成了COVID-19症状指数（CSI）, 以评估检测-重检测的可靠性。使用Cronbach’s alpha评估内部一致性。 CSI由健康受试者完成以评估内部有效性。患者在COVID-19解析后6周完成了CSI, 以评估对变化的反应能力。

结果：94名COVID-19患者和55名健康者完成了评估。严重程度评分较高的症状是疲劳、头痛和肌痛。 Cronbach’s alpha值为0.801, 表明内部一致性很高。重检测可靠性足够（rs¼0.535, p¼.001）。 CSI总评分与SNOT-22之间的相关性较高（rs¼0.782； p <.001）, 支持较高的外部有效度。 COVID-19患者报告的CSI评分显著高于健康个体, 这表明其内部有效性足够。在COVID-19解析后, 平均CSI显著下降, 支持对特性变化的高反应性。

结论和意义：CSI是一种可靠且有效的患者报告结果问卷, 用于评估COVID-19患者的症状严重程度。

Keywords:

• COVID-19
• symptom
• patient-reported outcome questionnaire
• questionnaire
• SARS-CoV-2
• coronavirus
• follow-up
• clinical
• instrument
• validity

Acknowledgments

The UMONS team of the Anatomy Lab for the managing of the data.

Ethical approval

The study protocol was approved by the Institutional Ethics Committee of CHU Saint-Pierre (Brussels, Belgium; n° CHUSP20032020).

Informed consent

The patient electronic informed consent was obtained.

Disclosure statement

The authors have no conflict of interest.