@article{fdi:010077779,
  title = {{I}ntracluster correlation coefficients in the {G}reater {M}ekong {S}ubregion for sample size calculations of cluster randomized malaria trials},
  author = {{P}eerawaranun, {P}. and {L}andier, {J}ordi and {N}osten, {F}. {H}. and {N}guyen, {T}. {N}. and {H}ien, {T}. {T}. and {T}ripura, {R}. and {P}eto, {T}. {J}. and {P}hommasone, {K}. and {M}ayxay, {M}. and {D}ay, {N}. {P}. {J}. and {D}ondorp, {A}. and {W}hite, {N}. and von {S}eidlein, {L}. and {M}ukaka, {M}.},
  editor = {},
  language = {{ENG}},
  abstract = {{B}ackground: {S}ample size calculations for cluster randomized trials are a recognized methodological challenge for malaria research in pre-elimination settings. {P}ositively correlated responses from the participants in the same cluster are a key feature in the estimated sample size required for a cluster randomized trial. {T}he degree of correlation is measured by the intracluster correlation coefficient ({ICC}) where a higher coefficient suggests a closer correlation hence less heterogeneity within clusters but more heterogeneity between clusters. {M}ethods: {D}ata on u{PCR}-detected {P}lasmodium falciparum and {P}lasmodium vivax infections from a recent cluster randomized trial which aimed at interrupting malaria transmission through mass drug administrations were used to calculate the {ICC}s for prevalence and incidence of {P}lasmodium infections. {T}he trial was conducted in four countries in the {G}reater {M}ekong {S}ubregion, {L}aos, {M}yanmar, {V}ietnam and {C}ambodia. {E}xact and simulation approaches were used to estimate {ICC} values for both the prevalence and the incidence of parasitaemia. {I}n addition, the latent variable approach to estimate {ICC}s for the prevalence was utilized. {R}esults: {T}he {ICC}s for prevalence ranged between 0.001 and 0.082 for all countries. {T}he {ICC} from the combined 16 villages in the {G}reater {M}ekong {S}ubregion were 0.26 and 0.21 for {P}. falciparum and {P}. vivax respectively. {T}he {ICC}s for incidence of parasitaemia ranged between 0.002 and 0.075 for {M}yanmar, {C}ambodia and {V}ietnam. {T}here were very high {ICC}s for incidence in the range of 0.701 to 0.806 in {L}aos during follow-up. {C}onclusion: {ICC} estimates can help researchers when designing malaria cluster randomized trials. {A} high variability in {ICC}s and hence sample size requirements between study sites was observed. {R}ealistic sample size estimates for cluster randomized malaria trials in the {G}reater {M}ekong {S}ubregion have to assume high between cluster heterogeneity and {ICC}s. {T}his work focused on u{PCR}-detected infections; there remains a need to develop more {ICC} references for trials designed around prevalence and incidence of clinical outcomes. {A}dequately powered trials are critical to estimate the benefit of interventions to malaria in a reliable and reproducible fashion.},
  keywords = {{ICC} ; {M}alaria ; {P}revalence ; {I}ncidence ; {C}luster randomized trial ; {S}ample size ; {P}.falciparum ; {P}. vivax ; {B}ootstrapping ; {MYANMAR} ; {VIET} {NAM} ; {CAMBODGE} ; {LAOS} ; {MEKONG} {REGION}},
  booktitle = {},
  journal = {{M}alaria {J}ournal},
  volume = {18},
  numero = {1},
  pages = {art. 428 [9 ]},
  year = {2019},
  DOI = {10.1186/s12936-019-3062-x},
  URL = {https://www.documentation.ird.fr/hor/fdi:010077779},
}