Systemic sclerosis: changes in the incidence rates in the Finnish population during the years 1999-2018

OBJECTIVE

The aim of our study was to examine changes in the incidence of systemic sclerosis (SSc) in Finland using two different classification criteria.

METHOD

Medical records of patients who had been registered with ICD-10 code M34 from 1999 to 2018 in two university hospitals were reviewed retrospectively. This period was divided into 5 year periods: 1999-2003, 2004-2008, 2009-2013, and 2014-2018. Using American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) 2013 criteria and clinical findings, we reclassified patients into four groups: diffuse SSc, limited SSc, sine SSc, or early SSc. In the same population, we also investigated whether the ACR 1980 criteria were fulfilled.

RESULTS

In 1999-2018, 246 new patients with SSc and 45 patients with early SSc were identified using ACR/EULAR 2013 criteria. Of these patients, 70 fulfilled the ACR 1980 criteria. Using ACR/EULAR 2013 criteria, the increase in new diagnoses was statistically significant when comparing the fourth period with the first period (p = 0.0012). The increase was due to a rise in limited SSc. Mean annual incidence rates in these groups were 0.9, 1.2, 1.9, and 2.8 per 100 000 inhabitants ≥ 16 years old. An increasing trend was also seen when using ACR 1980 criteria, but this was not statistically significant.

CONCLUSION

The incidence of SSc increased during the period between 1999-2003 and 2014-2018 using ACR/EULAR 2013, but not using ACR 1980 criteria. The increase was detected within a limited SSc subclass, owing to more sensitive classification criteria.

Differential diagnostics of polymyalgia rheumatica in a university hospital in Finland

OBJECTIVES

Diagnosing polymyalgia rheumatica (PMR) can be difficult as many conditions present with similar symptoms and findings. This study aimed to analyse how often the diagnosis of PMR changes during follow-up in a university hospital setting and to determine the most common clinical conditions initially misdiagnosed as PMR.

METHOD

All patients with a new primary diagnosis of PMR on at least one visit during the years 2016-2019 were identified from the hospital discharge register of Turku University Hospital, Finland. A diagnosis of PMR was confirmed if the patient met at least one of the five classification criteria, complete clinical follow-up (median 34 months) was compatible with PMR, and no other diagnosis better explained their condition.

RESULTS

Of the patients initially diagnosed with PMR, 65.5% were considered to have PMR after further evaluation and clinical follow-up. The most common conditions initially diagnosed as PMR were inflammatory arthritides (34.9%), degenerative or stress-related musculoskeletal disorders (13.2%), infection (9.3%), malignancy (9.3%), giant cell vasculitis (6.2%) and other vasculitis (6.2%), and a wide range of other less common diseases. The diagnosis of PMR remained in 81.3% of patients who fulfilled the 2012 American College of Rheumatology/European League Against Rheumatism PMR classification criteria and in 45.5% of patients who did not.

CONCLUSIONS

Diagnosing PMR is challenging, even in a university hospital. One-third of the initial diagnoses of PMR changed during further evaluation and follow-up. There is a substantial risk of misdiagnosis, especially in patients with atypical presentation, and the differential diagnoses of PMR must be considered carefully.

The validity of rheumatoid arthritis diagnoses in Finnish biobanks

OBJECTIVE

The aim of this study was to determine the validity of rheumatoid arthritis (RA) diagnoses in patients participating in Finnish biobanks.

METHOD

We reviewed the electronic medical records of 500 Finnish biobank participants: 125 patients with at least one visit with a diagnosis of seropositive RA, 125 patients with at least one visit with a diagnosis of seronegative RA, and 250 age- and gender-matched controls. The patients were chosen from five different biobank hospitals in Finland. A rheumatologist reviewed the medical records to assess whether each patients' diagnosis was correct. The diagnosis was compared with the diagnostic codes in the Finnish Care Register for Health Care (CRHC) and special reimbursement data of the Social Insurance Institution of Finland.

RESULTS

The positive predictive value (PPV) of CRHC diagnosis of RA (for seropositive and seronegative RA combined) was 0.82. For patients with a special reimbursement for anti-rheumatic medications for RA, the PPV was 0.89. The PPV was higher in patients with more than one visit. For one, two, five, and 10 visits, the PPV was 0.82, 0.85, 0.89, and 0.90, respectively, and for patients who also had the special reimbursement, the PPV was 0.89, 0.91, 0.93, and 0.94 for one, two, five, and 10 visits, respectively. In patients positive for anti-citrullinated protein antibodies, the PPV was 0.98.

CONCLUSION

These results demonstrate that the validity of RA diagnoses in Finnish biobanks was good and can be further improved by including data on special reimbursement for medication, number of visits, and serological data.

The validity of systemic sclerosis diagnoses in two university hospitals in Finland

OBJECTIVE

This study aimed to determine the validity of systemic sclerosis (SSc) diagnoses in Finnish university hospitals.

METHOD

Electronic medical records for 385 patients with a registered diagnosis of SSc (ICD-10 code M34) in two Finnish university hospitals from 2008 to 2018 were reviewed to assess whether each patient's diagnosis was correct.

RESULTS

The positive predictive value (PPV) of a diagnosis of SSc was 0.66 when fulfilment of the 2013 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for SSc was required; the PPV was 0.75 if patients meeting the 2001 LeRoy and Medsger classification criteria for early SSc were also included. When a diagnosis of SSc was made in a department of rheumatology, the PPV was 0.78, and 0.90 when including patients with early SSc. For the more specific diagnosis of limited cutaneous SSc (lcSSc), the PPV was 0.80, and 0.95 when including early SSc. For an lcSSc diagnosis made in rheumatology, the PPV was 0.81, and 0.97 with early SSc included.

CONCLUSION

These results demonstrate that in these two Finnish university hospitals, the diagnostic validity of a diagnosis of SSc was good if it was diagnosed in the department of rheumatology. For a more specific diagnosis of lcSSc, the most prevalent form of SSc in Finland, the validity was good even when registered in any department.

POS1383 DIFFERENTIAL DIAGNOSTICS OF POLYMYALGIA RHEUMATICA IN A UNIVERSITY HOSPITAL IN FINLAND

Background

Polymyalgia rheumatica (PMR) is an inflammatory disease that causes muscle pain and morning stiffness, especially in the shoulders and hips. Diagnosing PMR can be difficult, as the diagnosis is mainly clinical without a definitive diagnostic test, and many symptoms and findings of PMR may also be present in other conditions. There is little recent data on differential diagnostics of PMR.

Objectives

The aim of our study was to analyse patients diagnosed with polymyalgia rheumatica (PMR) in Turku University Hospital in Finland and determine how often a competing diagnosis better explaining the patients’ symptoms was found during further evaluation and clinical follow-up. We also aimed to find out what are the most common conditions initially misdiagnosed as PMR.

Methods

All patients with a new primary diagnosis of PMR (International Classification of Diseases – 10th revision [ICD-10] code M35.3) on at least one (in- or outpatient) visit during years 2016–2019 were identified from the hospital discharge register of Turku University hospital in Finland. We did a chart review of the patient charts including the full clinical follow-up period (median 34 months). We studied how often the primary diagnosis of PMR changed after further diagnostic evaluation or during follow-up.

Results

In 125 (32.7%) of the 382 patients, the initial diagnosis of PMR changed during further diagnostic evaluation or follow-up. Most common diagnoses initially misdiagnosed as PMR were inflammatory arthritides 36.0% (45/125), degenerative or stress-related musculoskeletal disorder 12.8% (16/125), infection 9.6% (12/125), malignancy 9.6% (12/125), giant cell vasculitis 6.4% (8/125) and other vasculitis 6.4% (8/125) (Table 1). Diagnosis changed in 19% (39/207) of patients fulfilling the 2012 ACR/EULAR PMR classification criteria and in 49% (86/175) of patients who did not.

Table 1.

Demographic and clinical characteristics of the study sample.

Number of patients382Female (%)218 (57.1%)Age at diagnosis in years [IQR]70.0 [64.0–77.8]Follow-up in months [IQR]34.0 [21.0–49.0]Diagnosed in rheumatology (%)299 (79%)Treated in rheumatology (%)310 (81%)Nr. of visits [IQR]6.5 [3.0–12.0]Diagnosis changed during follow-up (%)125 (32.7%)Final diagnosis in 125 patients whose initial diagnosis of PMR changedInflammatory arthritides (%)45 (36.0%)Degenerative or stress-related musculoskeletal disorder (%)16 (12.8%)Infection (%)12 (9.6%)Malignancy (%)12 (9.6%)Giant cell vasculitis (%)8 (6.4%)Other vasculitis (%)8 (6.4%)Other rheumatological disease (%)7 (5.6%)Fibromyalgia or other chronic pain syndrome (%)4 (3.2%)Gout or other crystal arthropathy (%)2 (1.6%)Endocrinological disease (%)2 (1.6%)Other or unknown (%)14 (11.2%)

Continuous variables are expressed as medians with interquartile ranges, and categorical variables are described as counts with percentages.

Conclusion

In a university hospital setting, a third of initial diagnoses of PMR were changed during further evaluation and follow-up. Our findings highlight that thorough consideration of differential diagnosis is always essential when diagnosing PMR. Especially in patients with atypical presentation, there is a substantial risk for misdiagnosis.

Disclosure of Interests

Johanna Paltta: None declared, Saara Suuronen: None declared, Laura Pirilä Consultant of: Has received consulting fees from Novartis, UCB, Pfizer, Lilly, Roche, Sanofi, Abbvie, Bristol-Myers-Squibb, Jansen-Cilag, Celgene and MSD, all unrelated to this work, Antti Palomäki Speakers bureau: Has received a lecture fee from Pfizer and Sanofi, all unrelated to this work, Consultant of: Has received consulting fees from Pfizer, Amgen and Abbvie, all unrelated to this work

Evaluation of a New Skeletal Troponin I Assay in Patients with Idiopathic Inflammatory Myopathies

BACKGROUND

The current biomarkers for diagnosis and monitoring of injured and diseased skeletal muscles, such as creatine kinase (CK), have limited tissue specificity and incapability to differentiate between pathological and physiological changes. Thus, new biomarkers with improved diagnostic accuracy are needed. Our aim was to develop and validate a novel assay for skeletal troponin I (skTnI), and to assess its clinical performance in patients with idiopathic inflammatory myopathies (IIM).

METHODS

A two-step fluoroimmunoassay was used to analyze samples from healthy reference individuals (n = 140), patients with trauma (n = 151), and patients with IIM (n = 61).

RESULTS

The limit of detection was 1.2 ng/mL, and the upper reference limit (90th percentile) was 5.2 ng/mL. The median skTnI concentrations were <limit of detection (LoD), 2.7 ng/mL, and 8.6 ng/mL in reference, trauma, and IIM cohorts, respectively. Differences in measured skTnI levels were statistically significant between all three study cohorts (Kruskal-Wallis P < 0.001; Mann-Whitney P < 0.001 for all). skTnI and CK had a strong positive correlation (Spearman's r = 0.771, P < 0.001), and the longitudinal changes in skTnI mirrored those observed with CK.

CONCLUSIONS

With the skTnI assay, patients with IIM were identified from healthy individuals and from patients with traumatic muscular injuries. When compared to CK, skTnI appeared to be more accurate in managing patients with low-grade IIM disease activities. The developed assay serves as a reliable analytical tool for the assessment of diagnostic accuracy of skTnI in the diagnosis and monitoring of myopathies.

AB1251 VALIDITY OF RHEUMATOID ARTHRITIS DIAGNOSES IN FINNISH BIOBANK PATIENTS

Background:

Finnish healthcare registers are used in medical research, but there is little data about the validity of these registers in rheumatology.

Objectives:

The aim of our study was to determine the validity of rheumatoid arthritis (RA) diagnoses in patients participating in the Finnish Biobanks.

Methods:

We reviewed the electronic patient charts of 125 patients with at least one visit with a diagnosis of seropositive RA, 125 patients with at least one visit with a diagnosis of seronegative RA and 250 age-and-sex matched controls. Patients were randomly selected from Finnish biobank participants. We evaluated whether the patients’ diagnosis of RA recorded in the hospital discharge registry at the participating hospital was correct according to chart review and expert opinion. In the control group it was investigated whether the diagnosis of RA was written in the patients’ chart, but the diagnosis code was not recorded.

Results:

The positive predictive value (PPV) of a single hospital registry diagnosis of seropositive RA was 0.74 but rose to 0.98 in patients with a special reimbursement for seropositive RA and 0.98 in anti-citrullinated protein antibody positive patients. For seronegative RA, the PPV of a diagnosis was 0.72 and in patients with a special reimbursement for seronegative RA 0.89. The PPV was higher in patients with more than one visit with the diagnosis: 0.92 if the patients had at least 5 visits with seropositive RA and 0.88 with at least 5 visits with seronegative RA. Negative predictive value for RA diagnosis was 0.99.

Conclusion:

These results demonstrate that the validity of RA diagnoses in healthcare registers can be markedly improved with data about special reimbursement for medication, number of visits and serological data.

Disclosure of Interests:

Antti Palomäki Consultant of: Pfizer, Speakers bureau: Pfizer, Sanofi, MSD, Johanna Paltta Consultant of: Lilly, Abbvie, Laura Pirilä Consultant of: Novartis, MSD Finland, Roche, Bristol-Myers-Squibb, Pfizer, Sanofi, Abbvie, Oy Eli LIlly Finland Ab, UCB Pharma Oy Finland, Jansen-Cilag, Mylan, Sandoz, Boehringer-Ingelheim, Paid instructor for: Boehringer -Ingelheim, MSD Finland, Speakers bureau: Boehringer-Ingelheim, Pfizer Finland, Hanna-Kaisa Heikkilä: None declared, Pia Isomäki Consultant of: Abbvie, BMS, Eli Lilly, MSD, Novartis, Pfizer, Roche, Sanofi, Johanna Huhtakangas Consultant of: Boehringer Ingelheim, Tuulikki Sokka-Isler: None declared, Oili Kaipiainen-Seppänen Speakers bureau: Boehringer Ingelheim, Kari Eklund Consultant of: Celgene, Lilly, Speakers bureau: Pfizer, Roche

Adhesion of bacteria to resected human colonic tissue: quantitative analysis of bacterial adhesion and viability

Adhesion to the intestinal mucosa is considered to be one of the main selection criteria of lactic acid bacteria for probiotic use. Adhesive probiotics are, for example, considered to provide better antagonism against pathogenic bacteria when compared to non-adhesive strains. Here a new model is described for studying adhesion and interaction of probiotic and pathogenic bacteria in the intestinal mucus in which the intestinal microbiota is present. The model is based on the use of human intestinal tissue, fluorescent-tagged bacteria and confocal laser scanning microscopy (CLSM) in adhesion measurements as well as human intestinal mucus and bioluminescent-tagged bacteria in viability measurements. Use of CLSM enabled, for the first time, real-time three-dimensional observations of live probiotic bacteria in their natural environment, the intestinal mucosa. When the real-time measurement of bacterial adhesion was combined with the real-time sensitive measurement of bacterial viability, it could be studied whether or not the adherent pathogens were alive. The model was used to study the interaction between Lactobacillus rhamnosus GG and Salmonella enterica serovar Typhimurium. We show that L. rhamnosus GG did not affect the adhesion or the viability of S. enterica serovar Typhimurium. Instead S. enterica serovar Typhimurium was shown to decrease the adhesion of L. rhamnosus GG in displacement assays. Moreover, the method is suitable for studies in which the interaction of two or more bacteria is examined in an environment in which other bacteria are present.

Measurement of bacterial adhesion—in vitro evaluation of different methods

The adhesion of bacteria to host tissue is the first step in pathogenesis. Similarly, bacterial adhesion to inanimate surfaces is the first step in formation of biofilms-a real problem in industrial processes and medical devices. Various agents capable of blocking the adhesion of bacteria to surfaces have been identified, such as probiotics, which are supposed to prevent the adhesion of pathogenic bacteria to the intestinal mucosa. Although measurement of bacterial adhesion is important itself, especially when agents used to prevent adhesion are developed, a relative small number of techniques can be used in the measurement of adhesion. These techniques are not well validated and there is lack of studies where those methods are compared to each other. Here we have compared different commonly used methods to measure adhesion of bacteria; radioactive labelling, fluorescence tagging, and staining of bacteria. The methods were used to measure the adhesion of Escherichia coli and Salmonella enterica serovar Typhimurium to intestinal mucus. Moreover, selected probiotic strains were used to study whether probiotics or the adhesion method used affected the results. As a result, we show that the best reproducibility and sensitivity were obtained using radioactive labelling. With other methods, the sensitivity was too low due to poorly adhering bacteria and low signal-to-background ratio.

Rapid screening method for the detection of antimicrobial substances

Bioluminescence is phenomenon where living organisms produce light and this production is directly dependent on metabolic activity of the organism. Genes encoding enzymes, luciferases, responsible for light production can be cloned into indicator strains, thus allowing sensitive detection of antimicrobial activity. This study utilized bacterial luciferase genes cloned into Staphylococcus aureus, Escherichia coli and Salmonella enterica serovar Typhimurium indicator strains and showed that the detection of antimicrobial activity can be obtained already in 2 h without laborious plate counting and overnight incubation. Indicator strains used in the study harboured luxAB genes responsible of producing light as well as luxCDE genes for synthesis of long-chain fatty aldehyde as substrate for light production. As a consequence, no exogenous aldehyde addition was needed allowing stable light production. Furthermore, the method was used for the detection of antimicrobial activity from lactic acid bacteria after the effect of organic acids was eliminated.