Widmaier EP, Raff H, Strang KT (2011) Vander’s human physiology. The mechanisms of body function. McGraw Hill, New York
Google Scholar
Choy E (2012) Understanding the dynamics: pathways involved in the pathogenesis of rheumatoid arthritis. Rheumatology 51(Suppl. 5):v3–v11. https://doi.org/10.1093/rheumatology/kes113
Rindfleisch JA, Muller D (2005) Diagnosis and management of rheumatoid arthritis. Am Fam Phys 72(6):1037–1047
Google Scholar
Grøn KL, Ørnbjerg LM, Hetland ML et al (2014) The association of fatigue, comorbidity burden, disease activity, disability and gross domestic product in patients with rheumatoid arthritis. Results from 34 countries participating in the Quest-RA program. Clin Exp Rheumatol 32(6):869–877
PubMed
Google Scholar
Dougados M, Soubrier M, Antunez A et al (2014) Prevalence of comorbidities in rheumatoid arthritis and evaluation of their monitoring: results of an international, cross-sectional study (COMORA). Ann Rheum Dis 73(1):62–68. https://doi.org/10.1136/annrheumdis-2013-204223
Article
PubMed
Google Scholar
National Rheumatoid Arthritis Society of the United Kingdom (2012) The impact of rheumatoid arthritis co-morbidities. http://www.nras.org.uk/data/files/Impact%20of%20RA%20Co-morbidities.pdf. Accessed 26 April 2016
Meghani SH, Buck HG, Dickson VV et al (2013) The conceptualization and measurement of comorbidity: a review of the interprofessional discourse. Nurs Res Pract 2013:192782. https://doi.org/10.1155/2013/192782
PubMed
PubMed Central
Google Scholar
Al-Bishri J, Attar SM, Bassuni N, Al-Nofaiey Y, Qutbuddeen H, Al-Harthi S, Subahi S (2013) Comorbidity profile among patients with rheumatoid arthritis and the impact on prescriptions trend. Clin Med Insights Arthritis Musculoskelet Disord 6:11–18. https://doi.org/10.4137/CMAMD.S11481
CAS
Article
PubMed
PubMed Central
Google Scholar
Michaud K, Wolfe F (2007) Comorbidities in rheumatoid arthritis. Best Pract Res Clin Rheumatol 21(5):885–906. https://doi.org/10.1016/j.berh.2007.06.002
Article
PubMed
Google Scholar
Osiri M, Sattayasomboon Y (2013) Prevalence and out-patient medical costs of comorbid conditions in patients with rheumatoid arthritis. Joint Bone Spine 80(6):608–612. https://doi.org/10.1016/j.jbspin.2013.01.013
Article
PubMed
Google Scholar
Petri H, Maldonato D, Robinson NJ (2010) Data-driven identification of co-morbidities associated with rheumatoid arthritis in a large US health plan claims database. BMC Musculoskelet Disord 11:247. https://doi.org/10.1186/1471-2474-11-247
Article
PubMed
PubMed Central
Google Scholar
Council for Medical Schemes (2017) Which chronic diseases are covered? https://www.medicalschemes.com/medical_schemes_pmb/chronic_disease_list.htm. Accessed 15 May 2017
Council for Medical Schemes (2017) The importance of ICD10. https://www.medicalschemes.com/medical_schemes_pmb/ICD-10_codes.htm. Accessed 24 Mar. 2016
Council for Medical Schemes (2017) What are PMBs? https://www.medicalschemes.com/medical_schemes_pmb/index.htm. Accessed 15 May 2017
SAS 9.4® (Statistical Analysis System®). SAS Institute Inc., pp 2002–2012
Petersen J, Maree K (2016) Overview of some of the most popular statistical techniques. In: Maree K (ed) First steps in research, 2nd edn. Van Schaik, Pretoria, pp 249–304
Google Scholar
Swanepoel JWH, Swanepoel CJ, Van Graan FC, Allison JS, Santana L (2010) Elementary statistical methods. AndCork, Potchefstroom
Google Scholar
Parekh AK, Goodman RA, Gordon C, Koh HK (2011) Managing multiple chronic conditions: a strategic framework for improving health outcomes and quality of life. Public Health Rep 126(4):460–471. https://doi.org/10.1177/003335491112600403
Article
PubMed
PubMed Central
Google Scholar
Barnett K, Mercer SW, Norbury M, Watt G, Wyke S, Guthrie B (2012) Epidemiology of multimorbidity and implications for health care, research, and medical education: a cross-sectional study. Lancet 380(9836):37–43. https://doi.org/10.1016/S0140-6736(12)60240-2
Article
PubMed
Google Scholar
Steyn HS (2012) Manual for the determination of effect size indices and practical significance. http://www.nwu.ac.za/content/statcs-effect-size. Accessed 26 April 2016
Luban S, Li ZG (2010) Citrullinated peptide and its relevance to rheumatoid arthritis: an update. Int J Rheum Dis 13(4):284–287. https://doi.org/10.1111/j.1756-185X.2010.01553.x
Article
PubMed
Google Scholar
World Health Organization (2016) Chronic rheumatic conditions. http://www.who.int/chp/topics/rheumatic/en/. Accessed 1 August 2016
Council for Medical Schemes (2009) Invitation to participate in clinical advisory committees on the revision of specific PMBs and to submit it proposals. Summary of Clinical Response from Wyeth South Africa (Pty) Ltd as requested on 20th August 2009. https://www.medicalschemes.com/files/PMB%20Review/WyethSummary_20090828.pdf. Accessed 1 July 2016
Ally MMTM., Visser CC (2010) Rheumatoid arthritis. S Afr Orthop J 9(1):18–23
Google Scholar
Alamanos Y, Drosos AA (2005) Epidemiology of adult rheumatoid arthritis. Autoimmun Rev 4(3):130–136. https://doi.org/10.1016/j.autrev.2004.09.002
Article
PubMed
Google Scholar
Wandai M, Aagaard-Hansen J, Day C, Sartorius B, Hofman KJ (2017) Available data sources for monitoring non-communicable diseases and their risk factors in South Africa. S Afr Med J 107(4):331–337. https://doi.org/10.7196/SAMJ.2017.v107i4.11438
CAS
Article
PubMed
Google Scholar
Kourilovitch M, Galarza-Maldonado C, Ortiz-Prado E (2014) Diagnosis and classification of rheumatoid arthritis. J Autoimmun 48 49:26–30. https://doi.org/10.1016/j.jaut.2014.01.027
Article
Google Scholar
Suta C, Petcu L, Craiu E, Suta M (2015) Sex ratio and age in patients with rheumatoid arthritis. Data from a cohort in South-East Romania. Roman J Rheumatol 24(4):220–225
Google Scholar
Baser O, Burkan A, Baser E, Koselerli R, Ertugay E, Altinbas A (2013) Direct medical costs associated with rheumatoid arthritis in Turkey: analysis from national claims database. Rheumatol Int 33(10):2577–2584. https://doi.org/10.1007/s00296-013-2782-4
Article
PubMed
Google Scholar
Cojocaru IM, Silosi I, Vrabie CD, Tanasescu R (2010) Extra-articular manifestations in rheumatoid arthritis. Maedica 5(4):286–291
PubMed
PubMed Central
Google Scholar
Gullick NJ, Scott DL (2011) Co-morbidities in established rheumatoid arthritis. Best Pract Res Clin Rheumatol 25(4):469–483. https://doi.org/10.1016/j.berh.2011.10.009
Article
PubMed
Google Scholar
Fortin M, Bravo G, Hudon C, Vanasse A, Lapointe L (2005) Prevalence of multimorbidity among adults seen in family practice. Ann Fam Med 3(3):223–228. https://doi.org/10.1370/afm.272
Article
PubMed
PubMed Central
Google Scholar
Cutolo M, Kitas GD, van Riel PLCM. (2014) Burden of disease in treated rheumatoid arthritis patients: going beyond the joint. Semin Arthritis Rheum 43(4):479–488. https://doi.org/10.1016/j.semarthrit.2013.08.004
Article
PubMed
Google Scholar
Van Onna M, Boonen A (2016) The challenging interplay between rheumatoid arthritis, ageing and comorbidities. BMC Musculoskelet Disord 17:184. https://doi.org/10.1186/s12891-016-1038-3
Article
PubMed
PubMed Central
Google Scholar
Norton S, Koduri G, Nikiphorou E, Dixey J, Williams P, Young A (2013) A study of baseline prevalence and cumulative incidence of comorbidity and extra-articular manifestations in RA and their impact on outcome. Rheumatology 52(1):99–110. https://doi.org/10.1093/rheumatology/kes262
Article
PubMed
Google Scholar
Shisana O, Labadarios D, Rehle T et al (2014) South African National Health and Nutrition Examination Survey (SANHANES-1). HSRC Press, Cape Town
Google Scholar
Burger J, Lubbe M, Serfontein J, Ellis S (2017) A cross-sectional analysis of the association between age and gender and prescribed minimum benefit chronic disease list conditions among South Africans with concomitant hypertension, diabetes and dyslipidaemia. Afr Health Sci 17(1):88–98
Article
PubMed
PubMed Central
Google Scholar
Boyer JF, Gourraud PA, Cantagrel A, Davignon JL, Constantin A (2011) Traditional cardiovascular risk factors in rheumatoid arthritis: a meta-analysis. Joint Bone Spine 78(2):179–183. https://doi.org/10.1016/j.jbspin.2010.07.016
Al-Shawwa B, Al-Huniti N, Titus G, Abu-Hasan M (2006) Hypercholesterolemia is a potential risk factor for asthma. J Asthma 43(3):231–233. https://doi.org/10.1080/02770900600567056
CAS
Article
PubMed
Google Scholar