Prevalence and incidence of systemic lupus erythematosus in the adult population of Estonia

Studies have demonstrated considerable variability in systemic lupus erythematosus (SLE) incidence and prevalence estimates. Lack of reliable epidemiological data may hinder evidence-based health care planning. The aim of the present study was to estimate the prevalence and incidence of SLE in the Estonian adult population. The SLE billing cases were extracted from the Estonian Health Insurance Fund database 2006-2010 and verified using health care providers' databases. The patients' life status data for January 1, 2011, were retrieved from the Estonian Population Register. The calculations for the estimates' lower limits were based on verified cases only; the upper limits calculations also accounted for the billing cases for which clinical data were unavailable. The period prevalence of SLE was between 39 and 48 per 100,000 and incidence rate between 1.5 and 1.8 per 100,000 person-years. The point prevalence on January 1, 2011, was between 37 and 40 per 100,000. The estimates are comparable with internationally published figures and can be used to enhance evidence-based health care planning. The high percentage of billing cases that could not be verified using clinical data supports the argument that epidemiological studies based solely on administrative databases are usually of low reliability.

Finalisation and validation of the rheumatoid arthritis impact of disease score, a patient-derived composite measure of impact of rheumatoid arthritis: a EULAR initiative

OBJECTIVE

A patient-derived composite measure of the impact of rheumatoid arthritis (RA), the rheumatoid arthritis impact of disease (RAID) score, takes into account pain, functional capacity, fatigue, physical and emotional wellbeing, quality of sleep and coping. The objectives were to finalise the RAID and examine its psychometric properties.

METHODS

An international multicentre cross-sectional and longitudinal study of consecutive RA patients from 12 European countries was conducted to examine the psychometric properties of the different combinations of instruments that might be included within the RAID combinations scale (numeric rating scales (NRS) or various questionnaires). Construct validity was assessed cross-sectionally by Spearman correlation, reliability by intraclass correlation coefficient (ICC) in 50 stable patients, and sensitivity to change by standardised response means (SRM) in 88 patients whose treatment was intensified.

RESULTS

570 patients (79% women, mean ± SD age 56 ± 13 years, disease duration 12.5 ± 10.3 years, disease activity score (DAS28) 4.1 ± 1.6) participated in the validation study. NRS questions performed as well as longer combinations of questionnaires: the final RAID score is composed of seven NRS questions. The final RAID correlated strongly with patient global (R=0.76) and significantly also with other outcomes (DAS28 R=0.69, short form 36 physical -0.59 and mental -0.55, p<0.0001 for all). Reliability was high (ICC 0.90; 95% CI 0.84 to 0.94) and sensitivity to change was good (SRM 0.98 (0.96 to 1.00) compared with DAS28 SRM 1.06 (1.01 to 1.11)).

CONCLUSION

The RAID score is a patient-derived composite score assessing the seven most important domains of impact of RA. This score is now validated; sensitivity to change should be further examined in larger studies.

Elaboration of the preliminary Rheumatoid Arthritis Impact of Disease (RAID) score: a EULAR initiative

BACKGROUND

Current response criteria in rheumatoid arthritis (RA) usually assess only three patient-reported outcomes (PROs): pain, functional disability and patient global assessment. Other important PROs such as fatigue are not included.

OBJECTIVE

To elaborate a patient-derived composite response index for use in clinical trials in RA, the RA Impact of Disease (RAID) score.

METHODS

Ten patients identified 17 domains or areas of health relevant for inclusion in the score, then 96 patients (10 per country in 10 European countries) ranked these domains in order of decreasing importance. The seven most important domains were selected. Instruments were chosen for each domain after extensive literature research of psychometric properties and expert opinion. The relative weight of each of the domains was obtained from 505 patients who were asked to "distribute 100 points" among the seven domains. The average ranks of importance of these domains were then computed.

RESULTS

The RAID score includes seven domains with the following relative weights: pain (21%), functional disability (16%), fatigue (15%), emotional well-being (12%), sleep (12%), coping (12%) and physical well-being (12%). Weights were similar across countries and across patient and disease characteristics. Proposed instruments include the Health Assessment Questionnaire and numerical ratings scales.

CONCLUSION

The preliminary RAID score is a patient-derived weighted score to assess the impact of RA. An ongoing study will allow the final choice of questionnaires and assessment of validity. This score can be used in clinical trials as a new composite index that captures information relevant to patients.

Review: Vitamin D, immunity and lupus

The identification of vitamin D receptor in cells involved in the immune response and the discovery that activated dendritic cells produce vitamin D hormone suggested that vitamin D could exert immunoregulatory effects. Patients with autoimmune diseases such as multiple sclerosis, rheumatoid arthritis and systemic lupus erythematosus (SLE) show low 25-OH vitamin D serum levels. In particular, SLE patients have multiple risk factors for vitamin D deficiency and disease severity seems correlated with lower 25-OH vitamin D serum levels. Treatment of vitamin D deficiency could be particularly important in SLE patients due to concomitant insults on their tissues such as bone, and in view of the possible immunomodulatory effects exerted by vitamin D. Lupus (2008) 17, 6—10.

Circannual vitamin d serum levels and disease activity in rheumatoid arthritis: Northern versus Southern Europe

BACKGROUND

Greater intake of vitamin D has been associated with a lower risk of rheumatoid arthritis (RA) and low serum vitamin D together with higher prevalence of RA seem common among North European people when compared to Southern Europe.

OBJECTIVES

To evaluate serum 25-hydroxyvitamin D [25(OH)D] levels in female RA patients from North (Estonia) and South (Italy) Europe and to correlate them with the disease activity score (DAS28) during winter and summer.

METHODS

Fifty-four RA Italian patients (IP) and 64 RA Estonian patients (EP) were evaluated for serum 25(OH)D levels in winter and summer time, as well as for DAS28 score. Normal female controls (C) were 35 (IC) and 30 (EC) age-matched subjects, respectively. 25(OH)D concentrations were measured by a competitive radioimmunoassay. Statistical analysis was performed by "r" Pearson correlation, "t" Student with Bonferroni correction and by repeated ANOVA measures (summer and winter) with two factors (country and clinical status).

RESULTS

25(OH)D levels were found significantly higher in IP versus EP (p = 0.0116) both in winter and in summer time. Differences were observed also in controls. The variations (increase) of 25(OH)D levels between winter and summer were found significant (p = 0.0005) in both IP and EP. Differences were observed also in controls. No significant differences were found concerning 25(OH)D levels between RA patients and their controls in either country. Interestingly, a significant negative correlation between 25(OH)D and DAS28, was found in summer only in IP (r =-0.57, p < 0.0001) and in winter in EP (r =-0.40, p < 0.05).

CONCLUSION

Significantly lower 25(OH)D serum levels were observed in RA patients from North versus South Europe with a circannual rhythm in winter and summer time. In addition, 25(OH)D values showed a significant correlation (negative) with RA clinical status (DAS28) in both North and South European RA patients, suggesting possible effects of vitamin D among other factors on disease activity.

Altered circadian rhythms in rheumatoid arthritis patients play a role in the disease's symptoms

The circadian changes in the metabolism or nocturnal secretion of endogenous corticosteroids (reduction) observed in rheumatoid arthritis (RA) patients are responsible, in part, for the time-dependent changes that are observed in the inflammatory response and related early morning clinical symptoms of the disease. Melatonin (MLT), another circadian nocturnal hormone that is the secretory product of the pineal gland, has been implicated in the time-dependent RA inflammatory reaction with effects that are opposite to those of corticosteroids. As a consequence, altered functioning of the HPA axis (early morning reduced corticosteroid production) and of the pineal gland (night increased MLT production) found in RA patients, seem to be important factors in the appearance and perpetuation of the clinical circadian symptoms of the disease. Consistently, human proinflammatory Th1-type cytokine production (related to MLT stimulation) exhibits a diurnal rhythmicity with peak levels during the night and early morning, at a time when plasma cortisol (inducing the Th2-type cytokine production) is lowest and MLT is highest. Reduced daily light exposure as observed in northern Europe (Estonia), at least during the winter, might explain the higher and more prolonged serum MLT concentrations that were observed in northern RA patients, as well as some epidemiological features versus southern Europe patients.

Circadian melatonin and cortisol levels in rheumatoid arthritis patients in winter time: a north and south Europe comparison

BACKGROUND

Altered functioning of the hypothalamic-pituitary-adrenal axis and altered melatonin production might modulate the circadian symptoms in patients with rheumatoid arthritis.

OBJECTIVE

To investigate the influence of different winter photoperiods on the circadian rhythms of serum melatonin, cortisol, tumour necrosis factor alpha (TNFalpha), and interleukin 6 (IL6) in patients with rheumatoid arthritis from a north Europe country (Estonia) and a south Europe country (Italy).

METHODS

The patients from Estonia (n = 19) and Italy (n = 7) had similar disease severity and duration and were compared with healthy age and sex matched controls in the two countries. Blood samples were collected during the period January to February at 8 pm, 10 pm, midnight, 2 am, 4 am, 6 am, 8 am, and 3 pm. Melatonin was measured by radioimmunoassay using (125)I-melatonin. Serum cortisol, TNFalpha, and IL6 cytokines were assayed by standard methods.

RESULTS

Higher circadian melatonin concentrations from 10 pm and an earlier peak were observed in Estonian patients than in their age and sex matched controls (p<0.01). Starting from midnight, melatonin concentrations were significantly higher in the Estonian patients than in the Italian patients. No significant differences were observed for serum cortisol. Serum TNFalpha was higher (p<0.05) in Estonian patients than in their controls and was correlated with the melatonin levels.

CONCLUSIONS

In a north European country (Estonia), the circadian rhythm of serum concentrations of melatonin and TNFalpha in patients with rheumatoid arthritis were significantly higher than in matched controls or in rheumatoid patients from a south Europe country (Italy).