Epidemiology of systemic sclerosis: a multi-database population-based study in Tuscany (Italy)

Steady decrease in systemic sclerosis mortality rates at younger ages over the past five decades

OBJECTIVE

We aimed to assess SSc mortality by age in the general population over the past five decades.

METHODS

This is a population-based study using a national mortality database and the census data for all US residents. We calculated the proportions of deaths for SSc and for all other causes (non-SSc) by age, and calculated age-standardized mortality rates (ASMRs) for SSc and non-SSc, and the ratio of SSc-ASMR to non-SSc-ASMR by age groups for each year from 1968 through 2015. We performed joinpoint regression to estimate the average annual percent change (AAPC) for each of these parameters.

RESULTS

SSc was recorded as the underlying cause of death in 5457 decedents aged ≤44 years, 18 395 aged 45-64, and 22 946 aged ≥65 from 1968 through 2015. At ages ≤44, the proportion of annual deaths decreased more for SSc than for non-SSc: AAPC, -2.2% (95% CI, -2.4% to -2.0%) for SSc vs -1.5% (-1.9% to -1.1%) for non-SSc. Consistently, SSc-ASMR decreased from 1.0 (95% CI, 0.8-1.2) in 1968 to 0.4 (0.3-0.5) per million persons in 2015, a cumulative decrease of 60% at an AAPC of -1.9% (95% CI, -2.5% to -1.2%) at ages ≤44. The SSc-ASMR:non-SSc-ASMR ratio also decreased [cumulative -20%; AAPC -0.3% (95% CI, -1.15% to 0.55%)] in the ≤44-years group. In contrast, those aged ≥65 experienced a steep increase in the SSc-ASMR [cumulative 187.0%; AAPC 2.0% (95% CI, 1.8-2.2)] and the SSc-ASMR:non-SSc-ASMR ratio [cumulative 395.4%; AAPC 3.3% (95% CI, 2.9-3.7)].

CONCLUSION

Mortality for SSc has steadily decreased at younger ages over the past five decades.

Clinical significance of serum ferritin in patients with systemic sclerosis

Objective

The purpose of this study was to explore the clinical significance of serum ferritin (SF) in patients with systemic sclerosis (SSc).

Methods

The levels of SF were measured in 115 patients with SSc and 117 healthy controls (HCs). Clinical characteristics and laboratory indexes between the high ferritin SSc group and the normal ferritin SSc group were analyzed.

Results

The level of SF in SSc patients was significantly higher than that in HCs (319.78 [179, 554.33] ng/ml vs. 99 [49.03, 164.29] ng/ml, p < 0.01). Compared with the normal ferritin SSc group, the high ferritin SSc group was more likely to develop skin diffuse cutaneous SSc, fingertip arthralgia, and cardiac involvement. In addition, the levels of glutamine transaminase (GGT), alanine aminotransferase (ALT), creatine kinase (CK), creatine kinase isoenzyme‐MB (CK‐MB), lactate dehydrogenase (LD), immunoglobulin G (IgG), immunoglobulin A (IgA), C‐reactive protein (CRP), erythrocyte sedimentation rate (ESR), and the positive rate of anti‐Scl70 antibody in the high ferritin SSc group were significantly higher (each p < 0.05). SF was positively correlated with GGT, ALT, CK, CK‐MB, LD, IgA, CRP, and ESR (each p < 0.05). Multiple linear regression analysis showed that cardiac involvement, ALT, and ESR were independent influencing factors of SF in SSc.

Conclusion

Our study shows that the level of SF in patients with SSc is increased, and the elevated SF is related to abnormal liver function, myocardial involvement, inflammatory status, and production of autoantibodies in SSc. Cardiac involvement, ALT, and ESR are independent factors affecting SF in SSc.

Healthcare Burden of Rare Diseases: A Population-Based Study in Tuscany (Italy)

Patients with rare diseases (RDs) need tailored, continuous, and multidisciplinary hospital care. This retrospective cohort study aimed to analyse the healthcare burden of RD patients using a multi-database approach, by linking the data of the Rare Diseases Registry of Tuscany with the regional hospital discharge database. The study population included 21,354 patients diagnosed with a RD between 1 January 2000 and 31 December 2017. The healthcare burden was evaluated for all the RDs during 2009–2018 period. The hospitalisation rate (per 1000) decreased over the years, ranging from 606.9 in 2009 (95% CI: 589.2–625.0) to 443.0 in 2018 (95% CI: 433.2–453.0). A decrease in the average length of stay (LOS) was observed in the earlier years, followed by an increase up to a steady trend (8.3 days in 2018). The patients with RDs of metabolism and the genitourinary system showed the highest hospitalisation rate (903.3 and 644.0 per 1000, respectively). The patients with rare immune system disorders and diseases of the skin and subcutaneous tissue showed the highest LOS (9.7 and 9.5 days, respectively). The methodological approach presented in this population-based study makes it possible to estimate the healthcare burden of RDs, which is crucial in the decision-making and planning aimed at improving patient care.

Orphan Drug Use in Patients With Rare Diseases: A Population-Based Cohort Study

Background: Orphan drugs are used for the diagnosis, prevention and treatment of rare diseases that, in the European Union, are defined as disorders affecting no more than 5 persons in 10,000. So far, a total of around 800 orphan medicinal products have been approved by the European Medicines Agency, however the utilization profile of orphan drugs has yet to be explored. This study aimed at assessing the utilization profile of orphan drugs authorized for marketing by the Italian Medicines Agency using population-based data.

Methods: A total of 21 orphan drugs used in outpatient settings, approved in the European Union before or during the 2008–2018 period and involving 15 rare diseases, were included in the study. The monitored population included patients with one of the conditions surveilled by the population-based Tuscany Registry of Rare Diseases and diagnosed between 2000–2018. A multi-database approach was applied, by linking data from the registry with information collected in drug prescriptions databases. The prevalence and intensity of use were estimated for the selected orphan drugs and other non-orphan medications, used to treat the same rare disease and for which a change in the prevalence of use was hypothesized after authorization of the orphan drug.

Results: For some diseases (acquired aplastic anemia, tuberous sclerosis complex, most metabolic diseases) a low prevalence of orphan drugs use was observed (range between 1.1–12.5%). Conversely, orphan drugs were frequently used in hemophilia B, Wilson disease and idiopathic pulmonary fibrosis (maximum of 78.3, 47.6 and 41.8%, respectively). For hemophilia B and Leber’s hereditary optic neuropathy, there are currently no other medications used in clinical practice in addition to orphan drugs. Six orphan drugs were used for the treatment of pulmonary arterial hypertension, appearing the elective therapy for this disease, albeit with different utilization profiles (range of prevalence 1.7–55.6%).

Conclusion: To the best of our knowledge, this is the first study investigating the utilization profile of orphan drugs prescribed in a defined geographical area, and providing relevant information to monitor over time potential changes in the prevalence of these medications as well as in the health care decision making.

Discovering potential interactions between rare diseases and COVID-19 by combining mechanistic models of viral infection with statistical modeling

Recent studies have demonstrated a relevant role of the host genetics in the coronavirus disease 2019 (COVID-19) prognosis. Most of the 7000 rare diseases described to date have a genetic component, typically highly penetrant. However, this vast spectrum of genetic variability remains yet unexplored with respect to possible interactions with COVID-19. Here, a mathematical mechanistic model of the COVID-19 molecular disease mechanism has been used to detect potential interactions between rare disease genes and the COVID-19 infection process and downstream consequences. Out of the 2518 disease genes analyzed, causative of 3854 rare diseases, a total of 254 genes have a direct effect on the COVID-19 molecular disease mechanism and 207 have an indirect effect revealed by a significant strong correlation. This remarkable potential of interaction occurs for >300 rare diseases. Mechanistic modeling of COVID-19 disease map has allowed a holistic systematic analysis of the potential interactions between the loss of function in known rare disease genes and the pathological consequences of COVID-19 infection. The results identify links between disease genes and COVID-19 hallmarks and demonstrate the usefulness of the proposed approach for future preventive measures in some rare diseases.

Current Concepts on the Pathogenesis of Systemic Sclerosis

From the clinical standpoint, systemic sclerosis (SSc) is characterized by skin and internal organ fibrosis, diffuse fibroproliferative vascular modifications, and autoimmunity. Clinical presentation and course are highly heterogenous and life expectancy variably affected mostly dependent on lung and heart involvement. SSc touches more women than men with differences in disease severity and environmental exposure. Pathogenetic events originate from altered homeostasis favored by genetic predisposition, environmental cues and a variety of endogenous and exogenous triggers. Epigenetic modifications modulate SSc pathogenesis which strikingly associate profound immune-inflammatory dysregulation, abnormal endothelial cell behavior, and cell trans-differentiation into myofibroblasts. SSc myofibroblasts show enhanced survival and enhanced extracellular matrix deposition presenting altered structure and altered physicochemical properties. Additional cell types of likely pathogenic importance are pericytes, platelets, and keratinocytes in conjunction with their relationship with vessel wall cells and fibroblasts. In SSc, the profibrotic milieu is favored by cell signaling initiated in the one hand by transforming growth factor-beta and related cytokines and in the other hand by innate and adaptive type 2 immune responses. Radical oxygen species and invariant receptors sensing danger participate to altered cell behavior. Conventional and SSc-specific T cell subsets modulate both fibroblasts as well as endothelial cell dysfunction. Beside autoantibodies directed against ubiquitous antigens important for enhanced clinical classification, antigen-specific agonistic autoantibodies may have a pathogenic role. Recent studies based on single-cell RNAseq and multi-omics approaches are revealing unforeseen heterogeneity in SSc cell differentiation and functional states. Advances in system biology applied to the wealth of data generated by unbiased screening are allowing to subgroup patients based on distinct pathogenic mechanisms. Deciphering heterogeneity in pathogenic mechanisms will pave the way to highly needed personalized therapeutic approaches.

Survival of patients with rare diseases: a population-based study in Tuscany (Italy)

Background

Rare diseases (RDs) encompass a heterogeneous group of life-threatening or chronically debilitating conditions that individually affect a small number of subjects but overall represent a major public health issue globally. There are still limited data on RD burden due to the paucity of large population-based epidemiological studies. The aim of this research was to provide survival estimates of patients with a RD residing in Tuscany, Italy.

Methods

Cases collected in the Rare Diseases Registry of Tuscany with diagnosis between 1st January 2000 and 31th December 2018 were linked to the regional health databases in order to retrieve information on mortality of all subjects. Survival at 1, 5 and 10 years from diagnosis with 95% confidence intervals (CI) was estimated by sex, age class, nosological group and subgroup using the Kaplan–Meier method. The effect of sex, age and period of diagnosis (years 2000–2009 or 2010–2018) on survival was estimated using Cox proportional hazards regression.

Results

Survival at 1, 5 and 10 years from diagnosis was 97.3%, 88.8% and 80.8%, respectively. Respiratory diseases and peripheral and central nervous system disorders were characterized by the lowest survival at 5 and 10 years. Despite a modest higher prevalence of RDs among females (54.0% of the total), male cases had a significant increased risk of death (hazard ratio, HR 1.48, 95% CI 1.38–1.58). Cases diagnosed during 2010–2018 period had a risk of death significantly lower than those diagnosed during 2000–2009 (HR 0.81, 95% CI 0.82–0.96), especially for immune system disorders (HR 0.48, 95% CI 0.26–0.87), circulatory system diseases (HR 0.61, 95% CI 0.45–0.84) and diseases of the musculoskeletal system and connective tissue (HR 0.64, 95% CI 0.49–0.84).

Conclusions

An earlier diagnosis as well as the improvement in the efficacy of treatment resulted in a decreased risk of death over the years for specific RDs. The linkage between a population-based registry and other regional databases exploited in this study provides a large and accurate mass of data capable of estimating patients’ life-expectancy and increasing knowledge on the collective burden of RDs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01907-0.