LOw DosE Spironolactone, chlorThAlidone oR Combination in CKD Trial

Inclusion Criteria: * Study is limited to US Veterans * GFR estimated by race-independent CKD-EPI formula \< 45 ml/min/1.73m2 but 15 mL/min/1.73m2 * Hypertension * The investigators will use clinic AOBP of at least 135/85 to define hypertension * Treatment with antihypertensive drugs * This would require the use of at least one antihypertensive drug * One of the drugs should be either an ACE inhibitor or ARB or a beta-blocker at the time of randomization * Serum K 3.5 to 5.2 mEq/L at the time of randomization Exclusion Criteria: * Clinic AOBP of \>=160/100 mmHg * Use of: * SPL * eplerenone * amiloride * triamterene * finerenone * thiazide * thiazide-like drugs (CTD, HCTZ, metolazone, indapamide) or the use of K binders or fludrocortisone in the previous 4 weeks * K supplementation would be allowed * Myocardial infarction, heart failure hospitalization, or stroke 8 weeks prior to randomization * If the patient is only on an alpha blocker, as the sole antihypertensive drug, they will be excluded * Pregnant or breastfeeding women or women who are planning to become pregnant or those not using a reliable form of contraception * Known hypersensitivity or a prior documented adverse reaction to CTD or SPL