Patient adherence to prescribed medication instructions for dyspepsia: The DIAMOND-study

Figures & data

Table I. Intake fidelity

Intake fidelity concerning Antacids or placebo (q.i.d. pills): Items with answering scales	Correct	Incorrect
How do you usually take the medication from the large medication jar?	462 (92%)^a	43 (9%)
□ I take the pills with water
□ I dissolve the pills in water
□ I dissolve the pills in another beverage, such as milk or lemonade
□ I chew on the pills
□ I swallow the pills without chewing
□ Other
How often per day do you take the medication from the large medication jar? … times a day	431 (88%) (4 times)	60 (12%) (other)
How many pills from the large medication jar do you take per time? pills per time	457 (98%) (1 pill)	8 (2%) (other)
When do you take the medication from the large jar? (more answers possible)	359 (72%)^a2	83 (17%)
	55 (11%)^a1
□ After a meal	□ When I get up
□ Before a meal	□ When I go to bed
□ During a meal	□ Other

Intake fidelity concerning PPI or placebo (o.d. pills): Items with answering scales	Correct	Incorrect
How do you usually take the medication from the small medication jar?	502 (99%)^a	4 (1%)
□ I take the pills with water
□ I dissolve the pills in water
□ I dissolve the pills in another beverage, such as milk or lemonade
□ I chew on the pills
□ I swallow the pills without chewing
□ Other
How often per day do you take the medication from the small medication jar? … times a day	482 (98%) [once daily]	12 (2%) [other]
How many pills from the small medication jar do you take per time? pills per time	486 (99%) [1 pill]	4 (1%) [other]
When do you take the medication from the small jar? (More answers possible)	436 (86%)^a	69 (10%)
□ After a meal □ When I get up
□ Before a meal □ When I go to bed
□ During a meal □ Other
At what time do you take the medication from the large medication jar? First time: ...	318 (68%) [o.d. before q.i.d.]^b	partly 128 (27%) [o.d. together with q.i.d.]
At what time do you take the medication from the small medication jar? First time: ...		22 (5%) [o.d. after q.i.d.]

^aCorrect answers are given in bold or in [square brackets].

¹One correct answer, ²two correct answers

^bThe o.d. pill needs to be taken before or during breakfast, and the q.i.d. pill needs to be taken after breakfast.

Table II. Differences between patients with and patients without missing values.

	Completeness score for treatment step 1 (pill count)			Intake fidelity sum score
	Present (n =477)	Missing (n =176)	P-value	Present (n =405)	Missing (n =248)	P-value
Mean age (SD)	48 (15)	45 (14)	ns	47 (14)	47 (16)	ns
Male	43%	52%	<0.05	43%	50%	ns
Non-Caucasian	4%	12%	<0.001	4%	9%	<0.05
Started with treatment step 2	63%	42%	<0.001	63%	48%	<0.001

Table III. Completeness: Number of pills used per day.

Treatment step		n	Mean (SD)	Range	% of prescribed dose	n of partially adherent patients (<80%)	n of adherent patients (80–120%)	n of partially adherent patients (>120%)
Step 1: Five pills/day (q.i.d. plus o.d. pills)		477	3.90 (1.2)	0–8.8	78%	200 (42%)	271 (57%)	6 (1%)
q.i.d. pills	All q.i.d.	487	3.01 (1.0)	0–7.1	75%	240 (49%)	239 (49%)	8 (2%)
	Antacid (step-up)	246	2.99 (1.0)	0–6.7	75%	125 (51%)	118 (48%)	3 (1%)
	Placebo (step-down)	241	3.02 (1.1)	0.1–7.1	75%	115 (48%)	121 (50%)	5 (2%)
o.d. pills	All o.d.	477	0.89 (0.2)	0–2.0	89%	103 (22%)	359 (75%)	15 (3%)
	Placebo (step-up)	242	0.87 (0.2)^a	0–2.0	87%	59 (24%)	177 (73%)	6 (3%)
	PPI (step-down)	235	0.92 (0.2)^a	0.1–2	92%	44 (19%)	182 (77%)	9 (4%)
Step 2: b.i.d. pills
	All b.i.d.	288	1.68 (0.5)	0–4.0	84%	96 (33%)	182 (63%)	10 (4%)
	Step-up	158	1.66 (0.5)	0–4.0	83%	55 (35%)	98 (62%)	5 (3%)
	Step-down	130	1.72 (0.5)	0.1–3.6	86%	41 (32%)	84 (65%)	5 (4%)
Step 3: Five pills/day (q.i.d. plus o.d. pills)		181	3.58 (1.4)	0–6.1	72%	89 (49%)	91 (50%)	1 (1%)
q.i.d. pills	All q.i.d.	181	2.78 (1.2)	0–4.7	70%	100 (55%)	81 (45%)	–
	Antacid (step-up)	90	2.66 (1.3)	0–4.7	67%	50 (56%)	40 (44%)	–
	Placebo (step-down)	91	2.91 (1.1)	0.2–4.4	73%	50 (55%)	41 (45%)	–
o.d. pills	All o.d.	182	0.84 (0.2)	0–1.4	84%	54 (30%)	125 (69%)	3 (2%)
	Placebo (step-up)	90	0.85 (0.2)	0–1.4	85%	26 (29%)	62 (69%)	2 (2%)
	PPI (step-down)	92	0.84 (0.2)	0–1.3	84%	28 (30%)	63 (69%)	1 (1%)

^aP-value =0.02, difference between placebo o.d. pills and PPI in step 1 tested with Mann–Whitney U test. o.d.. once daily; b.i.d., twice daily; q.i.d., four times daily.

Table IV. Adherence over time.

Treatment step 1	Treatment step 2	Treatment step 3
653 patients started step 1	Of which 372 started step 2;	Of which 231 started step 3,
	106 (28%) partially adherent	90 (39%) were partially adherent
	182 (49%) were adherent	91 (39%) were adherent
Partially adherent: 206 pts (32%) (Including 1 patient who started with treatment step 2)	Partially adherent: 47 of 114 pts (41%)	Partially adherent: 17 of 27 (63%)
		Adherent: 4 of 27 (15%)
		Pill count missing: 6 of 27 (22%)
	Adherent: 46 of 114 pts (40%)	Partially-adherent: 20 of 37 (54%)
		Adherent: 13 of 37 (35%)
		Pill count missing: 4 of 37 (11%)
	Pill count missing: 21 of 114 pts (18%)	Partially adherent: 3 of 5 (60%)
		Adherent: 2 of 5 (40%)
		Pill count missing: 0
Adherent: 271 pts (42%)	Partially adherent: 44 of 184 (24%)	Partially adherent: 11 of 24 (46%)
		Adherent: 5 of 24 (21%)
		Pill count missing: 8 of 24 (33%)
	Adherent: 108 of 184 (59%)	Partially adherent: 24 of 78 (31%)
		Adherent: 42 of 78 (54%)
		Pill count missing: 12 of 78 (15%)
	Pill count missing: 32 of 184 (17%)	Partially adherent: 5 of 18 (28%)
		Adherent: 5 of 18 (28%)
		Pill count missing: 8 of 18 (44%)
Pill count missing: 176 pts (27%)	Partially adherent: 15 of 74 (20%)	Partially adherent: 4 of 11 (36%)
		Adherent: 5 of 11 (46%)
		Pill count missing: 2 of 11 (18%)
	Adherent: 28 of 74 (38%)	Partially adherent: 4 of 19 (21%)
		Adherent: 14 of 19 (74%)
		Pill count missing: 1 of 19 (5%)
	Pill count missing: 31 of 74 (42%)	Partially adherent: 2 of 12 (17%)
		Adherent: 1 of 12 (8%)
		Pill count missing: 9 of 12 (75%)

NB. Patients who used less than 80% or more than 120% of the pills prescribed per day are considered partially adherent, patients who used 80–120% are considered to be adherent. For treatment steps 1 and 3 100% means five pills per day, in treatment step 2 100% means two pills per day. For the patients who have a missing pill count, the number of pills per day could not be calculated because the medication jars were not returned or the treatment duration was unknown.

Box 1. Medication instructions.

Treatment step 1 and Treatment step 3	Treatment step 2
Large medication jar: (Antacid or placebo)	H2-receptor antagonist:
• 1 pill 4 times daily	• 1 pill 2 times daily
• Use 1 hour after a meal and before bedtime	• Use in the morning and before bedtime
• Chew properly	• Take with a little water, swallow whole
Small medication jar: (PPI or placebo)
• Once daily 1 pill
• Use before or during breakfast
• No chewing, take with a little water