Canadian Consensus Criteria – Page 2 – American ME and CFS Society

Data mining: comparing the empiric CFS to the Canadian ME/CFS case definition

Abstract:

This article contrasts two case definitions for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). We compared the empiric CFS case definition (Reeves et al., 2005) and the Canadian ME/CFS clinical case definition (Carruthers et al., 2003) with a sample of individuals with CFS versus those without. Data mining with decision trees was used to identify the best items to identify patients with CFS. Data mining is a statistical technique that was used to help determine which of the survey questions were most effective for accurately classifying cases. The empiric criteria identified about 79% of patients with CFS and the Canadian criteria identified 87% of patients. Items identified by the Canadian criteria had more construct validity. The implications of these findings are discussed.

Source: Jason LA, Skendrovic B, Furst J, Brown A, Weng A, Bronikowski C. Data mining: comparing the empiric CFS to the Canadian ME/CFS case definition. J Clin Psychol. 2012 Jan;68(1):41-9. doi: 10.1002/jclp.20827. Epub 2011 Aug 5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3228898/ (Full article)

Chronic fatigue syndrome: study of a consecutive series of 824 cases assessed in two specialized units

Abstract:

BACKGROUND AND OBJECTIVE: The chronic fatigue syndrome (CFS) is a disabling disorder. Few studies are available in our area on the prevalence and characteristics of CFS. Therefore, we carried out a study of a consecutive series of 824 cases diagnosed in two specialized units.

PATIENTS AND METHODS: We evaluated all of the CFS patients seen from January 2008 to June 2010. We analyzed social and demographic data, employment status, time of clinical evolution, trigger factors and onset, Fukuda and Canadian criteria, associated comorbidities and treatment.

RESULTS: A total of 824 patients were included, 748 (91%) woman, mean age 48±9 years. Average age of onset of symptoms was 35±11 years, time to diagnosis 108±88 month. A precipitating factor was identified in 481 (58%) patients, the onset was gradual in 517 (63%) and 515 (62.5%) were not employed. The most outstanding diagnostic criteria of Fukuda were prolonged generalized fatigue after exercise, sleep disturbance and impairments in concentration and short-term memory. The different groups of symptoms defined by the Canadian consensus showed that CFS is a homogeneous entity. Accompanying comorbidity phenomena were anxiety 691 (83%), sicca syndrome 678 (82%), fibromyalgia 450 (55%). A total of 63% of patients (520) received pharmacological treatment.

CONCLUSIONS: CFS is an illness that preferentially affects young women and results in employment absenteeism. The most relevant clinical features were prolonged generalized fatigue after exercise, neurocognitive impairment and sleep disturbance. In the evaluation of the patient, it is very important to apply the Canadian criteria and to assess comorbidity.

Comment in: Chronic fatigue syndrome: current situation. [Rev Clin Esp. 2011]

Source: Ruiz E, Alegre J, García Quintana AM, Aliste L, Blázquez A, Fernández de Sevilla T. Chronic fatigue syndrome: study of a consecutive series of 824 cases assessed in two specialized units. Rev Clin Esp. 2011 Sep;211(8):385-90. doi: 10.1016/j.rce.2011.02.013. Epub 2011 Jul 27. [Article in Spanish] https://www.ncbi.nlm.nih.gov/pubmed/21794854

Prevalence of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in three regions of England: a repeated cross-sectional study in primary care

Abstract:

BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or chronic fatigue syndrome (CFS) has been used to name a range of chronic conditions characterized by extreme fatigue and other disabling symptoms. Attempts to estimate the burden of disease have been limited by selection bias, and by lack of diagnostic biomarkers and of agreed reproducible case definitions. We estimated the prevalence and incidence of ME/CFS in three regions in England, and discussed the implications of frequency statistics and the use of different case definitions for health and social care planning and for research.

METHODS: We compared the clinical presentation, prevalence and incidence of ME/CFS based on a sample of 143,000 individuals aged 18 to 64 years, covered by primary care services in three regions of England. Case ascertainment involved: 1) electronic search for chronic fatigue cases; 2) direct questioning of general practitioners (GPs) on cases not previously identified by the search; and 3) clinical review of identified cases according to CDC-1994, Canadian and Epidemiological Case (ECD) Definitions. This enabled the identification of cases with high validity.

RESULTS: The estimated minimum prevalence rate of ME/CFS was 0.2% for cases meeting any of the study case definitions, 0.19% for the CDC-1994 definition, 0.11% for the Canadian definition and 0.03% for the ECD. The overall estimated minimal yearly incidence was 0.015%. The highest rates were found in London and the lowest in East Yorkshire. All but one of the cases conforming to the Canadian criteria also met the CDC-1994 criteria, however presented higher prevalence and severity of symptoms.

CONCLUSIONS: ME/CFS is not uncommon in England and represents a significant burden to patients and society. The number of people with chronic fatigue who do not meet specific criteria for ME/CFS is higher still. Both groups have high levels of need for service provision, including health and social care. We suggest combining the use of both the CDC-1994 and Canadian criteria for ascertainment of ME/CFS cases, alongside careful clinical phenotyping of study participants. This combination if used systematically will enable international comparisons, minimization of bias, and the identification and investigation of distinct sub-groups of patients with possibly distinct aetiologies and pathophysiologies, standing a better chance of translation into effective specific treatments.

Source: Nacul LC, Lacerda EM, Pheby D, Campion P, Molokhia M, Fayyaz S, Leite JC, Poland F, Howe A, Drachler ML. Prevalence of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in three regions of England: a repeated cross-sectional study in primary care. BMC Med. 2011 Jul 28;9:91. doi: 10.1186/1741-7015-9-91. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3170215/ (Full article)

Severe versus Moderate criteria for the new pediatric case definition for ME/CFS

Abstract:

The new diagnostic criteria for pediatric ME/CFS are structurally based on the Canadian Clinical Adult case definition, and have more required specific symptoms than the (Fukuda et al. Ann Intern Med 121:953-959, 1994) adult case definition.

Physicians specializing in pediatric ME/CFS referred thirty-three pediatric patients with ME/CFS and 21 youth without the illness. Those who met ME/CFS criteria were separated into Severe and Moderate categories. Significant differences were found for symptoms within each of the six major categories: fatigue, post-exertional malaise, sleep, pain, neurocognitive difficulties, and autonomic/neuroendocrine/immune manifestations.

In general, the results showed participants who met the Severe ME/CFS criteria reported the highest scores, the Moderate ME/CFS group show scores that were a little lower, and the control group evidenced the lowest scores. Findings indicate that the Pediatric Case Definition for ME/CFS can distinguish between those with this illness and controls, and between those with Severe versus Moderate manifestations of the illness.

Source: Jason L, Porter N, Shelleby E, Till L, Bell DS, Lapp CW, Rowe K, De Meirleir K. Severe versus Moderate criteria for the new pediatric case definition for ME/CFS. Child Psychiatry Hum Dev. 2009 Dec;40(4):609-20. doi: 10.1007/s10578-009-0147-8. Epub 2009 Jun 10.https://www.ncbi.nlm.nih.gov/pubmed/19513826

Definitions and aetiology of myalgic encephalomyelitis: how the Canadian consensus clinical definition of myalgic encephalomyelitis works

Abstract:

A perspective on the various definitions of myalgic encephalomyelitis and the process of discovering its aetiology is presented. The importance of clinical guidelines is emphasised to encourage clinicians to provide clear descriptions of their individual patients required for proper clinical activity; diagnosis, estimation of severity of effect, prognosis, treatment and rehabilitation. This individual knowledge is informed by general and (hopefully) publicly confirmed knowledge resulting from scientific research during the second-person interaction which lies at the core of the clinical encounter. Both types of knowledge are essential.

Source: Carruthers BM. Definitions and aetiology of myalgic encephalomyelitis: how the Canadian consensus clinical definition of myalgic encephalomyelitis works. J Clin Pathol. 2007 Feb;60(2):117-9. Epub 2006 Aug 25. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1860613/ (Full article)