The efficacy of hydroxychloroquine (HCQ) in treating SARS-CoV-2 infection is harshly debated, with observational and experimental studies reporting contrasting results. To clarify the role of HCQ in Covid-19 patients, we carried out a retrospective observational study of 4,396 unselected patients hospitalized for Covid-19 in Italy (February-May 2020). Patients' characteristics were collected at entry, including age, sex, obesity, smoking status, blood parameters, history of diabetes, cancer, cardiovascular and chronic pulmonary diseases, and medications in use. These were used to identify subtypes of patients with similar characteristics through hierarchical clustering based on Gower distance. Using multivariable Cox regressions, these clusters were then tested for association with mortality and modification of effect by treatment with HCQ.
Disentangling the Association of Hydroxychloroquine Treatment with Mortality in Covid-19 Hospitalized Patients through Hierarchical Clustering. Di Castelnuovo A, Gialluisi A, Antinori A, Berselli N, Blandi L, Bonaccio M, Bruno R, Cauda R, Costanzo S, Guaraldi G, Menicanti L, Mennuni M, My I, Parruti G, Patti G, Perlini S, Santilli F, Signorelli C, Stefanini G, Vergori A, Ageno W, Agodi A, Agostoni P, Aiello L, Al Moghazi S, Arboretti R, Aucella F, Barbieri G, Barchitta M, Bonfanti P, Cacciatore F, Caiano L, Cannata F, Carrozzi L, Cascio A, Castiglione G, Ciccullo A, Cingolani A, Cipollone F, Colomba C, Colombo C, Crisetti A, Crosta F, Danzi GB, D'Ardes D, de Gaetano Donati K, Di Gennaro F, Di Tano G, D'Offizi G, Fusco FM, Gaudiosi C, Gentile I, Gianfagna F, Giuliano G, Graziani E, Guarnieri G, Langella V, Larizza G, Leone A, Maccagni G, Magni F, Maitan S, Mancarella S, Manuele R, Mapelli M, Maragna R, Marcucci R, Maresca G, Marongiu S, Marotta C, Marra L, Mastroianni F, Mengozzi A, Meschiari M, Milic J, Minutolo F, Mussinelli R, Mussini C, Musso M, Odone A, Olivieri M, Palimodde A, Pasi E, Pesavento R, Petri F, Pivato CA, Poletti V, Ravaglia C, Righetti G, Rognoni A, Rossato M, Rossi I, Rossi M, Sabena A, Salinaro F, Sangiovanni V, Sanrocco C, Schiano Moriello N, Scorzolini L, Sgariglia R, Simeone PG, Spinicci M, Tamburrini E, Torti C, Trecarichi EM, Vettor R, Vianello A, Vinceti M, Virdis A, De Caterina R, Iacoviello L. J Healthc Eng. 2021 Jun 25;2021:5556207. doi: 10.1155/2021/5556207