Background/Purpose: Polymyalgia Rheumatica (PMR) is an inflammatory disorder that predominantly affects older adults. Incidence peaks at 70-80 years old [1] and is more common in people of Scandinavian and northern European descent [2].Patients have widespread pains, stiffness, and muscle tenderness. The annual incidence is 64 per 100,000 population. Incidence is higher in females with a mean of 74 years [3].

While the exact cause of PMR is unknown, emerging research suggests a potential association between PMR and environmental triggers such as vaccination and infections [4]. It has been postulated that viral infections can incite an aberrant immune response, activating autoimmune processes [5]. Since the start of the coronavirus disease 2019 (COVID) pandemic, studies have suggested that the infection might trigger an inflammatory state, leading to an autoimmune response [6,7].

In our descriptive analysis, we look at patients who were referred to our academic Rheumatology clinics for long COVID symptoms. We also try to address how patients who develop PMR following COVID infection may differ from long COVID patients who do not.

Methods: This is a retrospective study in an academic rheumatology clinic, 132 adults (age >18 years) patients with an initial referral for persistent symptoms post-COVID infection (fatigue, myalgia, joints pains, stiffness, abnormal labs, rash) diagnosed between March 2020 and July 2021 were included using the unified record system at our institute. All patients had a documented positive COVID polymerase chain reaction test before the first rheumatology office visit.

Numeric variables were summarized using means and standard deviations or using medians and intra-quartile ranges. Categorical variables were summarized by counts and percentages. Numeric variables were compared by t-tests or Wilcoxon rank sum tests. Categorical variables were compared by chi-square or Fishers exact tests. 

Results: Thirty of 132 patients had persistent arthralgia, stiffness, and myalgias and were diagnosed with long COVID syndrome prior to their rheumatology clinic visit.

Eight of 30 patients were diagnosed with PMR. Patients with PMR had a higher mean age (79 vs 59, p< 0.001), and a higher median ESR (48.5 vs 12.0, p=0.013). No statistically significant difference between the two groups regarding gender, ethnicity, severity of initial COVID infection, duration of symptoms, and Rheumatoid factor (RF) positivity was detected. (Table 1)

All 8 patients with PMR diagnosis were responsive to steroid taper and achieved remission within one year. One patient required steroid-sparing medication (Leflunomide). Two patients had newly diagnosed neoplasms within 1 year (uterine cancer and chronic myeloid leukemia).

Conclusion: Our study was consistent with patients having long-COVID symptoms experiencing a higher incidence of PMR. As might be expected with the small sample size, there was no statistical difference in demographic characteristics between our PMR population and those without PMR. We aim to stimulate further investigation into the etiology, pathogenesis, and potential therapeutic interventions for PMR and related autoimmune disorders triggered by COVID.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-comprehensive-retrospective-analysis-of-polymyalgia-rheumatica-in-long-covid-patients-at-an-academic-medical-center-in-the-midwest/