Does basal adjustment affect bolus units!

My understanding is that basal should not impact bolus.
However, if your basal is too low, you would need more bolus to keep your BG level.
Likewise, if your basal was too high, it may be also providing some "bolus functionality".

If you have just changed your basal, I would hesitate before drawing too many conclusions. As there are so many things which can affect our BG, I always wait until I have observed the same results more than once before making any changes to the bolus.

Yes i have tried this and found that when i adjust my basal it affects my bolus. Etc for me, if i inject 3 units lantus i need to inject 2 unit novorapid for 25g carbs. If i inject 6 units lantus i inject 1 unit novorapid for 25g carbs to get similar blood glucose readings.

I agree with @helensaramay that your basal does not affect your bolus, however if you're running higher as a result of reducing your basal dose then yes you will need more bolus to correct and if you're taking too much basal then you may need to reduce your bolus.

You have asked this question before @azizdhl so it's important you understand the role of each insulin to fully answer your question. A simple explanation is: A basal-bolus routine involves taking a long acting basal insulin to keep blood glucose levels stable through periods of fasting and separate injections of short acting bolus insulin to prevent rising blood glucose levels resulting from eating food.

The aim with basal insulin is to achieve a steady blood sugar level when you are not eating, doing exercise or anything else which affects blood glucose. Easier said than done but that's the idea. Bolus insulin should theoretically then be just to cover the carbohydrates eaten.
As @helensaramay says, if your basal is not enough, blood sugars will drift upwards & then you will end up correcting with more bolus insulin. If your basal is too much then you end up correcting with carbs, and using less bolus insulin.
If you can afford a Libre or Dexcom CGM, even for a short time, then that will make basal adjustment much easier.
Getting a CGM showed that Lantus was very inconsistent for me - changing to Levemir has been a big improvement.

@azizdhl What others have said is correct, but I don't read it as basal not affecting bolus. I'd say that if your basal levels are incorrect, it does affect what you use for bolusing.

When basal levels are too high, ie, if they cause your glucose levels to drop over time, then your carb ratio is generally less aggressive (ie 1u:20g) because carbs in your food are used to keep your glucose levels from going to low, whereas if your basal is too low, you end up with more aggressive carb ratios (ie 1u:5g) because the bolus tops up the basal.

That's why undertaking a basal test is generally a good thing, as it means that you are optimised. In addition, another compounding factor is that Lantus can be quite variable in its absorption, and if you're finding that is the case, that would also affect your bolusing.

Hi @azizdhl, As others have said there will be situations where basal and basal interact less or more. From my experience as a diabetic but not as professional advice or opinion:
Remember that if you have a high protein meal that some of that protein will be converted (up to 50%) to glucose which will appear in the blood stream about ? 3 to 4 hours after a meal. Whilst the short-acting insulin (bolus) taken before the meal will still have some effect, the basal insulin may also need to provide some effect to lower this BSL level.
The quicker the blood sugar level rises after a meal the more the bolus insulin will be needed and provided the short-acting (bolus) insulin can match the BSL rise to control that level the less that the basal will be doing except dealing with the between meals and overnight BSLs.
When I have an infection like a respiratory tract infection (cold, bronchitis etc). or after my 'flu vaccination I increase BOTH bolus (short-acting) insulin AND basal (long acting) insulin as the insulin resistance caused by the infection or vaccination will be affecting me all the time, 24 hours per day not just for meals etc.
You do need to check your query also with your doctor and diabetes nurse. Best Wishes.

Yes - tim200s is absolutely right in my opinion.

If you have higher basal than what is needed, also a lesser amount bolus is needed to lower BSLs
This will on the other hand easier give you hypos.
If your basal level is too low, you need more bolus to compensate, and to keep BSLs in range.
You possibly have to make correction-boluses this way more often.

This applies at least to my body, and my kind of insulins - I have tested...