Does a patient have a privilege to refuse to disclose confidential information?

Evidence Code section 994 provides, subject to statutory exceptions, that a "patient, whether or not a party, has a privilege to refuse to disclose,[119 Cal.App.3d 544] and to prevent another from disclosing, a confidential communication between patient and physician." To the extent that the privilege applies, it operates as a bar to discovery of even relevant information. (Code of Civ. Proc., 2016, subd. (b).) "(T)here can be no discovery of matter which is privileged." (Rudnick v. Superior Court, supra, 11 Cal.3d 924, 929, 114 Cal.Rptr. 603, 523 P.2d 643.)