To the Editors:
The coronavirus disease 2019 (COVID‐19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has caused a sudden and substantial increase in hospitalizations for pneumonia worldwide. 1 Although the reverse transcription PCR assay is a commonly used tool for the diagnosis of COVID‐19, the sensitivity of PCR is not high using oropharyngeal and nasopharyngeal swab specimens and depends on the time of collection and the collector. 2 , 3 The Japanese Respiratory Society (JRS) scoring system, consisting of six parameters, is a useful tool for the early presumptive diagnosis of mild‐to‐moderate atypical pneumonia, mainly Mycoplasma pneumoniae pneumonia. 4 These parameters were: (1) age < 60 years, (2) no or minor comorbid illness, (3) presence of stubborn cough, (4) absence of chest adventitious sounds, (5) no sputum or no identified aetiological agent by rapid diagnostic tests (Gram staining, urinary antigen tests and nasopharyngeal antigen test) and (6) a peripheral white blood cell (WBC) count of <10,000/μl. We evaluated whether the JRS scoring system could be adapted to the diagnosis of mild‐to‐moderate SARS‐CoV‐2 pneumonia.
This study was conducted at five institutions between February 2020 and June 2021, and assessed a total of 823 patients with SARS‐CoV‐2 pneumonia (335 had lineage B.1.1.7., also known as the Alpha variant; Table 1) and 202 patients with bacterial pneumonia. COVID‐19 was diagnosed with positive PCR results from sputum or nasopharyngeal swab specimens according to the protocol recommended by the National Institute of Infectious Diseases, Japan.
TABLE 1.
Underlying conditions and clinical findings in patients with SARS‐CoV‐2 pneumonia in the non‐Alpha variant and Alpha variant groups at the first examination
| Variables | Non‐Alpha variant | Alpha variant | p‐value |
|---|---|---|---|
| No. of patients | 488 | 335 | |
| Median age (IQR), years | 65 (46–76) | 64 (51–74) | 0.387 |
| No. of males/females | 302/186 | 227/108 | 0.889 |
| No. (%) of patients with comorbid illnesses | |||
| Diabetes mellitus | 100 (20.5) | 65 (19.4) | 0.723 |
| Chronic lung disease | 55 (11.3) | 43 (12.8) | 0.512 |
| Chronic heart disease | 38 (7.8) | 23 (6.9) | 0.685 |
| Cerebrovascular disease | 32 (6.6) | 20 (6.0) | 0.772 |
| Chronic renal disease | 31 (6.4) | 24 (7.2) | 0.671 |
| Neoplastic disease | 30 (6.1) | 14 (4.2) | 0.269 |
| Chronic liver disease | 15 (3.1) | 9 (2.7) | 0.834 |
| Autoimmune disease | 15 (3.1) | 7 (2.1) | 0.510 |
| No. (%) of patients with the following clinical signs and symptoms | |||
| History of fever (≥37.0°C) | 413 (84.6) | 295 (88.1) | 0.183 |
| Cough | 249 (51.0) | 209 (62.4) | 0.001 |
| Fatigue | 167 (35.9) | 110 (32.8) | 0.707 |
| Shortness of breath | 132 (27.0) | 109 (32.5) | 0.101 |
| Sore throat | 97 (19.9) | 68 (20.3) | 0.929 |
| Loss of taste | 65 (13.3) | 55 (16.4) | 0.228 |
| Anosmia | 54 (11.1) | 49 (14.6) | 0.134 |
| Headache | 54 (11.1) | 33 (9.9) | 0.644 |
| Diarrhoea | 51 (10.5) | 27 (8.1) | 0.276 |
| Sputum production | 49 (10.0) | 54 (16.1) | 0.013 |
| Runny nose | 36 (7.4) | 24 (7.2) | >0.999 |
| Joint pain | 28 (5.7) | 14 (4.2) | 0.338 |
| Chest pain | 18 (3.7) | 5 (1.5) | 0.083 |
| Muscle ache | 17 (3.5) | 4 (1.2) | 0.044 |
| Nausea or vomiting | 16 (3.3) | 14 (4.2) | 0.571 |
| Abdominal pain | 6 (1.2) | 1 (0.3) | 0.250 |
| Laboratory findings, median (IQR) | |||
| White blood cell count, /μl | 5100 (4295–6400) | 5400 (4400–7350) | 0.242 |
| No. (%) of patients with each pneumonia severity score a | |||
| 0 | 197 (40.4) | 57 (17.0) | <0.001 |
| 1 | 128 (26.2) | 134 (40.0) | <0.001 |
| 2 | 110 (22.5) | 88 (26.3) | 0.245 |
| 3 | 52 (10.7) | 56 (16.7) | 0.015 |
| Positive cases/no. (%) for the presumptive diagnosis of atypical pneumonia in different age groups | |||
| 20–29 years | 41/41 (100) | 29/29 (100) | >0.999 |
| 30–39 years | 54/54 (100) | 15/15 (100) | >0.999 |
| 40–49 years | 41/42 (97.6) | 37/37 (100) | >0.999 |
| 50–59 years | 53/63 (84.1) | 52/56 (92.9) | 0.164 |
| 60–69 years | 46/96 (47.9) | 30/71 (42.3) | 0.531 |
| 70–79 years | 29/112 (25.9) | 23/90 (25.6) | >0.999 |
| ≥80 years | 23/80 (28.8) | 7/37 (18.9) | 0.363 |
Note: Continuous values are presented as medians and IQRs and categorical/binary values as counts and percentages.
Abbreviations: IQR, interquartile range; JRS, Japanese Respiratory Society; SARS‐CoV‐2, severe acute respiratory syndrome coronavirus 2.
The severity of pneumonia was evaluated using predictive rules via the A‐DROP system (a 5‐point scoring system) proposed by the JRS guidelines: age over 70 years in men and over 75 years in women, dehydration, respiratory failure, orientation disturbance and low blood pressure. An A‐DROP score of 0–3 points was classified as mild‐to‐moderate pneumonia.
Matching rates to the six parameters of the JRS scoring system were identical in both non‐Alpha variant and Alpha variant groups, and high matching rates were observed in the following parameters: absence of chest adventitious sounds, 71.6% (non‐Alpha variant group, 73.2%; Alpha variant group, 69.3%); no sputum or no identified aetiological agent by rapid diagnostic tests, 87.1% (90.0% and 83.0%); and a peripheral WBC count of <10,000/μl, 97.6% (98.2% and 96.7%). The matching rates of the other three parameters were as follows: age < 60 years, 42.2% (43.0% and 40.9%); no or minor comorbid illness, 57.8% (57.8% and 57.9%); and presence of stubborn cough, 10.4% (9.4% and 11.9%). The sensitivity and specificity for the diagnosis of atypical pneumonia in patients with SARS‐CoV‐2 pneumonia based on four or more parameters were 58.3% (58.8% in the non‐Alpha variant group and 57.6% in the Alpha variant group, respectively) and 92.2%, respectively.
When the diagnostic sensitivity was analysed for different ages stratified into the 10‐year groups, the diagnostic sensitivity of patients in both the non‐Alpha variant and Alpha variant groups was highest in the 20–39‐year age group and decreased in order from the youngest to the oldest age group (Table 1). There was a clear difference between elderly (aged ≥60 years) and non‐elderly (aged <60 years) patients with SARS‐CoV‐2 pneumonia. The diagnostic sensitivity for SARS‐CoV‐2 pneumonia was 95.5% for non‐elderly patients and 32.5% for elderly patients.
Our results demonstrated that the JRS scoring system is a useful tool for distinguishing between SARS‐CoV‐2 pneumonia and bacterial pneumonia in patients aged <60 years, but not in patients aged ≥60 years.
CONFLICT OF INTEREST
None declared.
AUTHOR CONTRIBUTION
Conceptualization: Naoyuki Miyashita (lead), Yasushi Nakamori (equal), Makoto Ogata (supporting), Naoki Fukuda (supporting), Akihisa Yamura (supporting), Yoshihisa Ishiura (supporting), Shosaku Nomura (supporting). Data curation: Naoyuki Miyashita (lead), Yasushi Nakamori (lead), Makoto Ogata (supporting), Naoki Fukuda (supporting), Akihisa Yamura (supporting), Yoshihisa Ishiura (supporting), Shosaku Nomura (supporting). Formal analysis: Makoto Ogata (lead), Naoki Fukuda (equal). Funding acquisition: Yoshihisa Ishiura (lead), Shosaku Nomura (equal). Investigation: Naoyuki Miyashita (lead), Yasushi Nakamori (equal), Makoto Ogata (supporting), Naoki Fukuda (supporting), Akihisa Yamura (supporting), Yoshihisa Ishiura (supporting), Shosaku Nomura (supporting). Methodology: Makoto Ogata (lead), Naoki Fukuda (equal). Project administration: Naoyuki Miyashita (lead), Yasushi Nakamori (equal), Yoshihisa Ishiura (supporting), Shosaku Nomura (supporting). Resources: Naoyuki Miyashita (lead), Yasushi Nakamori (equal), Yoshihisa Ishiura (supporting), Shosaku Nomura (supporting). Software: Naoyuki Miyashita (lead), Yasushi Nakamori (equal), Yoshihisa Ishiura (supporting), Shosaku Nomura (supporting). Supervision: Naoyuki Miyashita (lead), Yasushi Nakamori (equal), Yoshihisa Ishiura (supporting), Shosaku Nomura (supporting). Validation: Yoshihisa Ishiura (lead), Shosaku Nomura (equal). Visualization: Makoto Ogata (lead), Naoki Fukuda (equal). Writing – original draft: Naoyuki Miyashita (lead), Yasushi Nakamori (equal). Writing – review & editing: Naoyuki Miyashita (lead), Yasushi Nakamori (equal), Makoto Ogata (supporting), Naoki Fukuda (supporting), Akihisa Yamura (supporting), Yoshihisa Ishiura (supporting), Shosaku Nomura (supporting).
HUMAN ETHICS APPROVAL STATEMENT
The study protocol was approved by the Ethics Committee of Kansai Medical University and all participating facilities (approval number 2020319). Informed consent was obtained from all individual participants in the study.
Miyashita N, Nakamori Y, Ogata M, Fukuda N, Yamura A, Ishiura Y, et al. Clinical differentiation of severe acute respiratory syndrome coronavirus 2 pneumonia using the Japanese guidelines. Respirology. 2022;27:90–92. 10.1111/resp.14173
Handling Editor: Philip Bardin
REFERENCES
- 1. Zhu N, Zhang D, Wang W, Li X, Yang B, Song J, et al. A novel coronavirus from patients with pneumonia in China, 2019. N Engl J Med. 2020;382:727–33. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2. Wang W, Xu Y, Gao R, Lu R, Han K, Wu G, et al. Detection of SARS‐CoV‐2 in different types of clinical specimens. JAMA. 2020;323:1843–4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3. Kucirka LM, Lauer SA, Laeyendecker O, Boon D, Lessler J. Variation in false‐negative rate of reverse transcriptase polymerase chain reaction‐based SARS‐CoV‐2 tests by time since exposure. Ann Intern Med. 2020;173:262–7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4. Committee for the Japanese Respiratory Society Guidelines for the Management of Respiratory Infections . Guidelines for the management of community acquired pneumonia in adults, revised edition. Respirology. 2006;11(Suppl 3):S79–133. [DOI] [PubMed] [Google Scholar]