Incidence of multiple sclerosis in Buenos Aires: a 16-year health maintenance organization-based study

Increasing Incidence and Prevalence of Multiple Sclerosis in Puerto Rico (2013-2016)

BACKGROUND

The incidence of multiple sclerosis (MS) has been increasing worldwide over the past decades. However, this upward trend has not been examined at the country level in Latin America and the Caribbean (LAC). The aims of this study are to examine trends of MS incidence over 4 years and to provide age- and gender-standardized incidence rate estimates for a Caribbean island.

METHODS

Data from the Puerto Rico (PR) MS Foundation's registry was used to identify all newly diagnosed MS cases between 2013 and 2016. MS patients were 18 years and older and met the 2010 revised McDonald criteria. Age- and gender-standardized incidence rates were estimated.

RESULTS

A total of 583 new MS cases were diagnosed in PR from 2013 to 2016. The age- and gender-standardized MS incidence rate for PR increased from 6.1/100,000 in 2013 to 6.7/100,000 in 2016. The annual age-standardized MS incidence rates for females rose from 8.4/100,000 in 2013 to 9.8/100,000 in 2016 and were higher than males, which remained around 3.7/100,000.

CONCLUSION

Incidence estimates for PR were higher than other LAC countries but consistent with MS increases in other world regions. Our findings tend to rule out several prior potential environmental explanations for high MS incidence rates.

Multiple sclerosis epidemiology in Latin America: An updated survey

Novel epidemiological data have appeared in recent years in Latin America (LATAM). The objective of this study was to perform an updated systematic review of the epidemiology of the disease reported in LATAM.

Structural sex differences at disease onset in multiple sclerosis patients

BACKGROUND

Male sex is associated with worsening disability and a more rapid progression of multiple sclerosis (MS). This study analysed structural sex differences in magnetic resonance images of the brain, comparing women whose disease started before and after the menopause with a control group of men.

METHODS

This was a case control study in which female patients whose MS started before (Group 1) and after (Group 2) the menopause were included. The control group was matched by age, disease duration, Expanded Disability Status Scale and disease-modifying treatment. Patients were analysed according to demographic and clinical variables, as well as in terms of radiological measurements at disease onset and during the first 12 months of follow-up. These measurements included normalised total brain volume (NTBV), normalised cortical volume (NCV), normalised white matter volume, left and right hippocampus, the thalamus, brain stem volume, lesion load and percentage brain volume change. A linear regression model was used to analyse the data.

RESULTS

A total of 97 patients were included: 53 in Group 1 (27 females) and 44 in Group 2 (22 females). In Group 1, we observed a reduction in brain volume in males compared with females at disease onset in NTBV (p = 0.01), NCV (p = 0.001) and brain stem volume (p = 0.01). We did not observe differences in Group 2 at disease onset in the brain volumes analysed.

CONCLUSION

We observed structural sex differences in brain volume at disease onset in the pre-menopausal group. However, no structural differences were observed at disease onset between the sexes after the menopause had started.

Increasing incidence of multiple sclerosis among women in Buenos Aires: a 22 year health maintenance organization based study

Studies in multiple sclerosis (MS) suggest a trend of increasing disease prevalence and incidence, and especially, a disproportional increase in the incidence of multiple sclerosis in women. The objective of this study was to evaluate the incidence of MS over 22 years and to determine the ratio in incidence of men to women in a health maintenance organization from Buenos Aires, Argentina. The population was made up of all members of a hospital-based HMO affiliated between January 1992 and December 2013. Each person was followed contributing time at risk. Cases with definite diagnosis of MS were included. Incidence density was calculated with 95 % confidence intervals and compared between women and men. 165,456 subjects were followed for a total of 1,488,575 person-years, of whom 42 developed MS. Incidence density was 3/100,000 person-years (95 % CI 2.1-3.5/100,000 person-years). During this period (1992-2013), the incidence rate in women increased from 1/100,000 (95 % CI 0.8-1.6) to 4.9/100,000 (95 % CI 4.1-5.4) (p < 0.001), while in men the incidence ranged from 1.4/100,000 (95 % CI 1-1.7) to 1.8 (1.3-2.1) (p = 0.16). Incidence density during the study period increased significantly in women but not in men. This is the first report of this phenomenon in Latin America region.

Incidence and Prevalence of Rheumatoid Arthritis in a Health Management Organization in Argentina: A 15-year Study

Objective.

To estimate incidence and prevalence rates of rheumatoid arthritis (RA) in the city of Buenos Aires (CABA), Argentina, using data from a university hospital–based health management organization.

Methods.

Global, age-specific, and sex-specific incidence and prevalence rates were calculated for members of the Hospital Italiano Medical Care Program (HIMCP), age ≥ 18 years. Incidence study followed members with continuous affiliation ≥ 1 year from January 2000 to January 2015 until he/she voluntarily left the HIMCP, RA was diagnosed, death, or study finalization. Cases from the Rheumatology Section database, electronic medical records, laboratory database, and pharmacy database were filtered with the 2010 American College of Rheumatology/European League Against Rheumatism criteria. Prevalence was calculated on January 1, 2015, and standardized for CABA. Capture-recapture (C-RC) analysis estimated true population sizes.

Results.

In the study period, incidence rates (cases per 100,000 person-yrs) were 18.5 (95% CI 16.7–20.4) overall, 25.2 (95% CI 22.4–28.0) for women, and 8.8 (95% CI 6.8–10.8) for men. Prevalence rates (percentage of RA cases in the sample population) were 0.329 (95% CI 0.298–0.359) overall, 0.464 (95% CI 0.417–0.510) for women, and 0.123 (95% CI 0.093–0.152) for men. Standardized CABA prevalence rate was 0.300 (95% CI 0.292–0.307). C-RC adjusted rates were almost the same as unadjusted rates.

Conclusion.

This study’s incidence and prevalence rates are in the lower range of the rates found around the world. Our female to male prevalence ratio was 4:1. Our peak incidence age was in the sixth and seventh decades for both sexes.

Is it time for a new global classification of multiple sclerosis?

BACKGROUND

The geographic distribution of multiple sclerosis (MS) is classically divided into three zones based on frequency that were established by Kurtzke in the early 1970s. In recent years, an increasing number of epidemiological studies have shown significantly higher MS prevalence and incidence rates.

OBJECTIVE

The aim of this study was to review and update the geographic distribution of MS using incidence, prevalence and disease duration from the latest epidemiology surveys.

METHODS

We conducted a systematic review of articles on MS epidemiology published between January 1, 1990 and December 31, 2012.

RESULTS

MS studies were grouped by continent: the Americas, Europe, Asia, Australia/New Zealand, and Africa. A total of 101 studies were identified according to the inclusion criteria, and 58 reported incidence estimates. Globally, the median estimated incidence of MS was 5.2 (range: 0.5-20.6) per 100,000 p-yrs, the median estimated prevalence of MS was 112.0 (with a range of 5.2-335) per 100,000 p-yrs, and the average disease duration was 20.2 years (range: 7.6-36.2).

CONCLUSION

In the past few decades, the global prevalence and incidence patterns of MS have changed dramatically. Regardless of the reason of increasing prevalence and incidence rate, we suggest the need for a novel classification system based on global MS disease burden. Adopting such a system would improve economic efficiency and prioritization in health policy planning for MS.

A retrospective case series of pediatric spinal cord injury and disease in Victoria, Australia

STUDY DESIGN

Retrospective case series.

OBJECTIVE

This study aimed to describe the incidence and etiology of pediatric spinal cord disorders (SCD) at The Royal Children's Hospital (RCH).

SUMMARY OF BACKGROUND DATA

Spinal cord disorders is rare in children, but those who sustain SCD typically require significant ongoing resources to optimize long-term outcomes. The incidence of pediatric SCD has been reported in Europe, North America, and South America; however, no previous reports are available for Australia.

METHODS

A retrospective case series of consecutive admissions with SCD was identified using the International Classification of Diseases and Related Health Problems, 10th Edition, Australian Modification, diagnostic codes relating to initial onset of SCD for both traumatic and nontraumatic conditions. Potential cases admitted to RCH between January 1, 2000, and June 30, 2010, were identified and the RCH Trauma Registry was cross-checked to improve accuracy of case attainment.

RESULTS

A total of 103 patients were admitted during the study period. Most patients (n = 68, 66%) had a nontraumatic SCD and were male (n = 68, 66%). Of the 68 patients who sustained nontraumatic spinal injuries, the majority (n = 40, 59%) were a result of neoplasm or transverse myelitis (n = 15, 22%) or other diseases of the spinal cord (n = 12, 18%). Thirty-five children were admitted after traumatic injury and more than half of these (n = 19, 54%) were involved in motor vehicle accidents, followed by sporting injuries (n = 8, 23%), falls from height (n = 7, 20%) and assault (n = 1, 3%). The average incidence of traumatic SCD and nontraumatic SCD during the study period was estimated at 3.8 and 6.5 per million children younger than 15 years, respectively.

CONCLUSION

The incidence of pediatric SCD at RCH is lower than reports from Europe and the United States but may be comparable on a population basis. The incidence of nontraumatic pediatric SCD is approximately double that of traumatic SCD.

LEVEL OF EVIDENCE

3.

The epidemiology of multiple sclerosis in Latin America and the Caribbean: a systematic review

The incidence and prevalence of multiple sclerosis (MS) varies geographically as shown through extensive epidemiological studies performed mainly in developed countries. Nonetheless, scant data is available in Latin America and the Caribbean (LAC). The objective of this review is to assess epidemiological data of MS in LAC. We conducted a systematic review of published articles and gray literature from January 1995 to May 2011. Twenty-two studies met the inclusion criteria after full-text review. Incidence data were found in only three studies and ranged from 0.3 to 1.9 annual cases per 100,000 person-years. Prevalence was reported in 10 studies and ranged from 0.83 to 21.5 cases per 100,000 inhabitants. The most prevalent subtype of MS was the relapsing–remitting form (48% to 91% of the series). No data about mortality were found. This study showed low frequency for MS in LAC compared with North American and European countries. The role of environmental and genetic factors should be well studied, providing new insights about its etiology.

Incidence of multiple sclerosis in Chile. A hospital registry study

OBJECTIVE

To study the incidence of MS in Chile by examining the hospitalizations across all geographical regions of the country and to examine whether there is a correlation between these rates and the latitude or ultraviolet radiation.

METHODS

This is a descriptive study examining the national registry of hospitalizations because of MS (code G35 in ICD-10) from January 1, 2001, to December 31, 2006. Incidence rates were calculated by gender and geographical region and standardized to the world population estimated for 2010.

RESULTS

A total of 6857 hospitalizations were analyzed. There were 935 individuals; 63.9% were women. The mean incidence rate for 2002-2006 period was 0,90 (95% CI: 0.75-1.05). The annualized incidence rates for regions from North to South were as follows: I Tarapaca 0.54 (95% CI: 0.0-1.21), II Antofagasta 0,93 (0.10-1.75), III Atacama 1.07 (0.0-2.31), IV Coquimbo 0.63 (0.01-1.24), V Valparaiso 0.83 (0.38-1.27), VI O'Higgins 0.72 (0.14-1.30), VII Maule 0.52 (0.06-0.98), VIII BIO BIO 0.81 (0.41-1.21), IX Araucanía 0.43 (0.0-0.86), X Los Lagos 0.91 (0.35-1.46), XI Aysen 0.99 (0.0-2.98), XII Magallanes 3.54 (0.57-6.51), and XIII Metropolitana 1.10 (0.84-1.36). There were no significant correlations between hospitalization rates and latitude, except for region XII. UV radiation levels showed significant differences only for region XII.

CONCLUSION

There is a moderate risk of MS in Chile. The southernmost region showed significantly higher incidence rates than those in the rest of the country (a cluster zone). We did not find any correlation between incidence rates and latitude or UV radiation.

Why does the north-south gradient of incidence of multiple sclerosis seem to have disappeared on the northern hemisphere?

The traditional view, based on numerous early studies and reviews, is that MS is particularly prevalent in temperate zones both on the northern and southern hemisphere. This uneven distribution of MS can be attributed to differences in genes and environment and their interaction. Diagnostic accuracy and case ascertainment are sources of error and have their shares in the geographical and temporal variations, and improvements in diagnostic accuracy and case ascertainment influence incidence- and prevalence rates. In addition the prevalence also depends on survival. With this meta-analysis we have focused on the trend in the incidence and sex ratio of MS through the last five decades, and we have analyzed the latitudinal distribution of MS incidence, based on a recent literature search. Our findings indicated that the prevalence and incidence rates had increased in almost all areas, but the previously reported latitudinal gradient of incidence of MS in Europe and North America could not be confirmed even when restricting the search to surveys published before 1980 or 1970. Conversely, the latitudinal gradient of prevalence rates seemed to be preserved. This apparent discrepancy can be explained by the circumstance that incidence estimates only depend on complete ascertainment for a relative short recent period of time, whereas reliable prevalence rates presuppose complete ascertainment decades back in time. A contributory explanation for the missing latitudinal gradient for incidence may be changes in environmental factors, levelling out differences in habits of life across Europe and North America, and, not least, that the interpretation of a latitudinal gradient in Europe was based primarily on prevalence studies and reviews. In addition, we observed in most regions a profound increase in female incidence of MS. The last observation should prompt epidemiological studies focusing on change in female life style.

Incidence and prevalence of psoriatic arthritis in Buenos Aires, Argentina: a 6-year health management organization-based study

OBJECTIVES

Studies regarding epidemiology of PsA are lacking in Latin America. We estimated the incidence and prevalence of PsA in a University Hospital-based Health Management Organization in Buenos Aires [Hospital Italiano Medical Care Program (HIMCP)].

METHODS

POPULATION

for incidence calculation, the population at risk was all adult members of the HIMCP, with continuous affiliation for at least 1 year from January 2000 to January 2006. Each person was followed until he/she voluntarily left the HIMCP, death or finalization of the study (final dates) contributing time at risk since January 2000 or enrolment date (whichever occurred later) to that final date. Case ascertainment: medical records of all patients with the problem psoriasis and/or PsA in the HIMCP problem-oriented computer-based patient record system, or registered in rheumatologists and/or dermatologists databases, were revised. Patients fulfilling CASPAR criteria were included.

STATISTICAL ANALYSIS

incidence rate (IR) was calculated with 95% CIs. Cumulative prevalence was estimated on 1 January 2006 (denominator population ==88,112).

RESULTS

In the study period, 138,288 persons contributed a total of 558,878 person-years, of whom 35 developed PsA (IR 6.26; 95% CI 4.2, 8.3 cases per 100,000 person-years). There were 12 females: IR 3.64 (95% CI 1.6, 5.7) cases per 100,000 person-years; and 23 males: IR 10.02 (95% CI 5.9, 14.1) cases per 100,000 person-years. On 1 January 2006, 65 prevalent cases were identified: prevalence 74 (95% CI 57, 94) cases per 100,000 members.

CONCLUSIONS

The incidence and prevalence of PsA in this Latin American country was similar to that reported in other studies from Europe and the USA.