title: Persistent arthralgia among Chikungunya patients and associated risk factors in Chennai, South India.
abstract: BACKGROUND
  Chikungunya (CHIK) fever is viral disease characterized by joint pain for prolonged duration in various settings. However, there are no reports of long-term follow-up of the CHIK patients from India.
  
  
  OBJECTIVE
  We conducted a cohort study to describe the clinical manifestations, incidence of persistent arthralgia, and the associated risk factors among patients with CHIK identified during an outbreak in a suburb of Chennai, India.
  
  
  METHODS
  We conducted a retrospective cum prospective cohort study in Gowripet, Avadi, Chennai. We included all adult CHIK case patients identified during the outbreak. We conducted a nested case-control study to identify the risk factors for persistent arthralgia defined as a CHIK case experiencing arthralgia for more than 15 days from the date of onset of illness. We included all 81 patients and 81 randomly selected controls.
  
  
  RESULTS
  All 403 case patients had joint pain. Approximately 40% suffered joint pain for up to 1 month and 7% had it beyond 1 year. The most commonly affected types of joints were knee (96%), wrist (80%), and ankle (77%) joints. Regarding the number of types of joints affected, 36% had six types of joints, 23% had five types of joints, and 14% had three types of joints affected. The overall incidence of persistent arthralgia was 80%. High-grade fever, involvement of four or more types of joints, and joint swelling were significantly associated with persistent arthralgia.
  
  
  CONCLUSIONS
  High prevalence of persistent arthralgia indicates the need for appropriate treatment strategies to reduce the severity and duration of joint pain.
authors.affiliation: National Institute of Epidemiology (ICMR), R-127, Tamil Nadu Housing Board, Ayapakkam, Chennai, Tamil Nadu, India.
authors.forename: V
authors.initials: V
authors.lastname: Ramachandran
authors.forename: P
authors.initials: P
authors.lastname: Kaur
authors.forename: K
authors.initials: K
authors.lastname: Kanagasabai
authors.forename: S
authors.initials: S
authors.lastname: Vadivoo
authors.forename: M V
authors.initials: MV
authors.lastname: Murhekar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000843:Ankle Joint; D018771:Arthralgia / Q000150:complications / Q000453:epidemiology* / Q000821:virology; D016022:Case-Control Studies; D065632:Chikungunya Fever / Q000150:complications / Q000453:epidemiology* / Q000821:virology; D004196:Disease Outbreaks; D005260:Female; D005334:Fever / Q000209:etiology*; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D007719:Knee Joint; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D014955:Wrist Joint; D055815:Young Adult